ANALYSIS OF THE INFLUENCE OF ECONOMIC INDICATORS ON STOCK PRICES USING MULTIPLE REGRESSION SYS 302 Spring 2000 Professor Tony Smith Yale Chang Carl Yeung Chris Yip TABLE OF CONTENTS I. INTRODUCTION A. Chosen Economic Variables B. Assumptions on the Regression Model II. ANALYSIS A. Single Regression Models of TCB 500 Against Indicators B. Preliminary Multiple Regression C. Multicollinearity D. Choosing Variables With the Stepwise Regression Model E. Gauss-Markov Assumptions: Heteroscedasticity and Autocorrelation F. Predictive Abilities of the Regression Models III. CONCLUSION A. Single Regression Discussion B. Multiple Regression Discussion IV. SUPPLEMENTS A. Appendix A B. Appendix B 1 I. INTRODUCTION Every month, anxious investors eagerly await the release of key economic indicators such as the employment report, CPI, and even housing starts. It is not uncommon for the Dow Jones Industrial Average and NASDAQ to swing more than a hundred points when the numbers only slightly miss consensus estimates. Every indicator is an important measure of some facet of the domestic economy, but do these numbers really shape the movement of stock prices in the long run? Which indicators yield the most influence on the equity market? Can a model consisting of these indicators be constructed to accurately forecast the stock market? And are any single indicators a good predictor of stock prices? As curious investors ourselves, we developed a statistical model in an attempt to detect a trend between stock prices and such variables and evaluated the predictive abilities of the model. Data was obtained from The Conference Board Economic Indicator Package, provided by Wharton Research Data Services (WRDS). Monthly time series data was obtained for stock market prices and a selection of economic indicators over a span of twenty years, from January 1979 to January 1999. This period was chosen because of the relative stability of the economy, the nation’s minimal exposure to severe external shock (i.e. wars), and the comprehensiveness of the data. The stock market index provided by the Conference Board is the TCB 500 common stock index, which is not commonly quoted; each data point represents the index’s closing price for the given month. This index was employed in our analysis because it represents the stock market more fully than the Dow Jones Industrial Average, which includes only thirty stocks. Furthermore, a 2 comparison of the TCB 500 and the SP500 revealed that the two indices are almost identical, as the single regression shows below: SPX By TCB 500 Stock 1300 1100 900 S 800 P X 600 500 300 100 0 0 100 300 500 700 500 Stock 900 1100 1300 Linear Fit Linear Fit SPX = 0.05124 + 1.00486 500 Stock Summary of Fit Rsquare 0.997687 RSquare Adj 0.997678 Root Mean Square Error 12.80636 Mean of Response 370.3486 Observations (or Sum Wgts) 241 A time series graph comparing the two indices is also shown below: SP 500 vs TCB 500 1400 1200 1000 TCB 500 SP 500 800 600 400 200 0 time (1979-1999) 3 A. Chosen Economic Indicators The variables included in our initial analysis compose only a portion of the complete set of economic indicators released monthly. The list below is by no means exhaustive, and each indicator was chosen to measure a distinct component of the economy. 1. Composite index of 10 leading indicators (1992 = 100) Labor force, employment, and unemployment: 2. Average weekly hours, manufacturing. (hours) 3. Average weekly initial claims, unemployment insurance (thousands) 4. Civilian unemployment rate (pct.) Sales, Orders, and Deliveries: 5. Manufacturers' new orders, consumer goods and materials (mil. chain 1992 $) 6. Vendor performance, slower deliveries diffusion index (pct.) 7. Manufacturing and trade sales (mil. Chain 1992 $) Output, Production, and Capacity Utilization: 8. Capacity utilization rate, total industry (pct.) Fixed Capital Investment: 9. Contracts and orders for plant and equipment (bil. chain 1992 $) 10. Building permits for new private housing units (thousands) Producer and Consumer Prices: 11. Producer Price Index, finished goods (1982=100) 12. CPI for all urban consumers, all items (1982-84=100) Commodity Prices: 13. Index of sensitive materials prices (level, 1992=100) Incln: Cattle hides (1982=100) Lumber and wood products (1982=100) Iron and steel scrap (1982=100) Copper base scrap (1982=100) Aluminum base scrap (1982=100) Nonferrous scrap, NSA (1982=100) Raw cotton (1982=100) Domestic apparel wool (1982=100) Personal Income: 14. Personal income less transfer payments (AR, bil. chain 1992 $) 15. Index of consumer confidence (1985=100) COPYRIGHTED (The Conf Bd) 4 16. Index of consumer expectations (1985=100) COPYRIGHTED (The Conf Bd) Money, Credit, Interest Rates, and Stock Prices: 17. Money supply, M2 (bil. chain 1992 $) 18. Interest rate spread, 10-year Treasury bonds less federal funds 19. Federal funds rate, NSA (pct.) Exports and Imports: 20. Exports, excluding military aid shipments (mil. $) - General imports (mil. $) = Trade Balance International Comparisions: 21. Exchange value of U.S. dollar, NSA (Mar. 1973=100) 5 B. Assumptions on the Regression Model 1. The basic assumption made on the data set was that the chosen economic indicators exert significant, observable influence on the price changes in the stock market. The relationship between the TCB 500 stock index level and the chosen indicators was assumed to be linear and subject to random error. 2. The different economic variables chosen are not released on the same day within a given month. For example, the employment survey is released the first Friday of every month, while the CPI is released the Tuesday of the third week. We have assumed that this difference in timing does not affect our correlation model. 3. The quarterly released indicator such as GDP and productivity were not included in our model since the time series data is on a monthly scale. While figures such as GDP undoubtedly play an important role in affecting stock prices, their inclusion in the model would most likely produce inconsistencies. 4. We have assumed that the TCB 500 index is a good proxy for the equity market. From the earlier discussion, we found that it does represent the S&P 500 index well. However, it is often argued that the S&P 500 is not the best measure of equity market movements since it is not mean and variance sufficient. 5. The Gauss-Markov model was not automatically assumed. Unique tests were conducted to examine the Gauss-Markov assumptions as well as heteroscedasticity and autocorrelation in order to derive an acceptable model. 6 II. ANALYSIS A. Single Regression Models of TCB 500 Against Indicators To begin our study, single regression models of the TCB 500 index were run against each economic indicator to obtain a graphical interpretation of how well each variable correlates with the stock market. The regression plots for each indicator are attached at the end of the report as Appendix A. These plots show that the only indicators which seem to display a smooth, consistent relationship with the TCB 500 index are the following: index of ten leading indicators, manufacturing and trade sales, CPI, and personal income. The polynomial fits of these four variables correlate surprisingly well with the stock index, with R2 values of at least 0.95 (see Appdendix B). With this information in mind, we proceeded to perform a preliminary multiple regression. B. Preliminary Multiple Regression While single regressions can be limited in their analysis, multiple regression models simultaneously take into account the effects of each variable. A standard least squares multiple regression was conducted, plotting the TCB 500 common stock index against all economic indicators. The results of the multiple regression are shown below: Response: 500 Stock Summary of Fit RSquare RSquare Adj Root Mean Square Error Mean of Response Observations (or Sum Wgts) Term Intercept 10 Leading Ind Avg Wkly Hr Parameter Estimates Estimate -2845.606 52.003024 -16.89806 7 0.987224 0.985999 31.25715 368.508 241 Std Error 879.1908 13.65247 11.42545 t Ratio -3.24 3.81 -1.48 Prob>|t| 0.0014 0.0002 0.1406 UE Claims Mfrs New Orders Vendor Prfm Bldg Permit M2 Intrt Rate Spre UE Rate Capacity Util R Mnfr & Trade Sa Cntrct & Orders PPI CPI Comd Prices Pers Inc Cnsmr Conf Cnsmr Expt FF Rate Trade Balance Ex Value USD Source 10 Leading Ind Avg Wkly Hr UE Claims Mfrs New Orders Vendor Prfm Bldg Permit M2 Intrt Rate Spre UE Rate Capacity Util R Mnfr & Trade Sa Cntrct & Orders PPI CPI Comd Prices Pers Inc Cnsmr Conf Cnsmr Expt FF Rate Trade Balance Ex Value USD 0.2057853 -0.003696 -0.738489 -0.162113 -0.564221 -18.52264 -0.023767 -18.84474 0.0046085 0.0024846 3.9181248 -17.05578 0.0406398 0.4029118 -3.88931 3.1739166 -9.068953 0.0001526 1.9144678 Nparm 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0.128894 0.001289 0.716969 0.024568 0.106776 3.92238 10.1186 3.565865 0.000586 0.001011 3.13577 2.667677 0.634698 0.097376 0.731443 0.659718 3.771536 0.00142 0.491674 Effect Test DF Sum of Squares 1 14175.342 1 2137.106 1 2490.361 1 8034.001 1 1036.540 1 42538.108 1 27280.134 1 21787.388 1 0.005 1 27286.563 1 60460.850 1 5895.660 1 1525.340 1 39936.970 1 4.006 1 16726.921 1 27623.796 1 22613.772 1 5649.062 1 11.283 1 14812.891 1.60 -2.87 -1.03 -6.60 -5.28 -4.72 -0.00 -5.28 7.87 2.46 1.25 -6.39 0.06 4.14 -5.32 4.81 -2.40 0.11 3.89 F Ratio 14.5089 2.1874 2.5490 8.2231 1.0609 43.5391 27.9221 22.3001 0.0000 27.9287 61.8836 6.0344 1.5612 40.8768 0.0041 17.1205 28.2738 23.1459 5.7820 0.0115 15.1615 0.1118 0.0045 0.3041 <.0001 <.0001 <.0001 0.9981 <.0001 <.0001 0.0148 0.2128 <.0001 0.9490 <.0001 <.0001 <.0001 0.0170 0.9145 0.0001 Prob>F 0.0002 0.1406 0.1118 0.0045 0.3041 <.0001 <.0001 <.0001 0.9981 <.0001 <.0001 0.0148 0.2128 <.0001 0.9490 <.0001 <.0001 <.0001 0.0170 0.9145 0.0001 This model shows an excellent fit, with almost 99% of the variance accounted for (R2 = 0.987); it appears that the available data is sufficient to describe the movement in stock prices. Not surprisingly, the four variables that demonstrated high correlation with the TCB 500 from the earlier single regressions have also produced highly significant pvalues here. 8 On the other hand, not all of the variables are significant, such as the trade balance, commodity prices, and the unemployment rate, which has a p-value of almost 1! It seems illogical to claim that what is probably the most closely watched measure of economic performance by Wall Street and the Fed has practically no effect on stock prices. It is also strange that the coefficients for CPI and PPI have opposite signs even though they both measure inflation. Similarly, the unemployment rate and unemployment claims also have a negative correlation, as well as consumer confidence and consumer expectations. C. Multicollinearity A possible explanation of these discrepancies might be multicollinearity, which undermines the significance of the individual coefficients. To refine the model, a correlation plot between the stock index and the economic indicators was drawn to determine which variables are highly dependent: Variable 10 Mfrs Avg UE Bldg Leading New Wkly Hr Claims Permit Indicies Orders 10 Leading Ind 1 Avg Wkly Hr 0.8968 M2 Intrt Rate Spread UE Rate Capacit Mnfr & Cntrct y Util Trade & Rate Sales Orders PPI CPI Pers Inc Cnsmr Cnsmr Conf Expt FF Rate Trade Ex Value Balance USD 0.8968 -0.7549 0.8954 0.2309 0.9665 0.4231 -0.6713 0.326 0.9075 0.7075 0.8576 0.897 0.9349 0.5724 0.3774 -0.8185 -0.8714 1 -0.4352 0.8156 -0.4955 0.7468 0.6852 0.3242 -0.5006 -0.84 -0.5305 0.9115 -0.812 0.9078 0.2123 0.8006 0.3059 -0.7067 0.5284 0.8699 0.6887 0.7707 0.8261 0.857 0.5383 0.2914 -0.7119 -0.797 UE Claims -0.7549 -0.812 Mfrs New Orders 0.8954 0.9078 -0.7392 1 -0.7392 -0.4653 -0.6496 -0.1116 0.7539 -0.6826 -0.6369 -0.6018 -0.4328 -0.5041 -0.6095 -0.7254 -0.4463 0.4645 Bldg Permit 0.2309 0.2123 -0.4653 0.1647 M2 0.9665 0.8006 -0.6496 0.8062 0.0964 Intrt Rate Spread 0.4231 0.3059 -0.1116 0.1685 0.1002 0.4068 UE Rate -0.6713 -0.7067 0.7539 -0.7852 -0.1259 -0.6457 0.1916 1 0.1647 0.8062 0.1685 -0.7852 0.5157 0.9746 0.8769 0.8053 0.878 0.9393 0.6249 0.2774 -0.6625 1 0.0964 0.1002 -0.1259 0.0688 0.0466 0.1329 -0.1604 -0.1047 -0.0072 0.5578 0.5351 1 -0.3827 0.4352 0.0489 0.915 0.4702 0.268 -0.8064 -0.8025 -0.4777 0.7652 0.1916 -0.2923 0.1944 -0.1141 0.4303 0.3864 0.2715 -0.1331 0.1745 -0.7336 -0.272 0.0488 0.114 0.6413 0.5733 -0.6377 0.4024 0.5588 0.1118 0.2052 0.339 0.5033 -0.0114 -0.0743 -0.2785 -0.5108 0.249 -0.5596 0.9541 0.4068 -0.6457 0.2577 0.8574 0.6436 0.8492 0.877 1 1 -0.13 500 Stock -0.8275 -0.7427 -0.8241 -0.4541 -0.5514 -0.7062 -0.6963 -0.1141 0.3413 Capacity Util Rate Mnfr & Trade Sales Cntrct & Orders 0.326 0.5284 -0.6826 0.5157 0.0688 0.2577 -0.2923 -0.8275 0.9075 0.8699 -0.6369 0.9746 0.0466 0.8574 0.1944 -0.7427 0.4024 0.7075 0.6887 -0.6018 0.8769 0.1329 0.6436 -0.1141 -0.8241 0.5588 0.8606 PPI 0.8576 0.7707 -0.4328 0.8053 -0.1604 0.8492 0.4303 -0.4541 0.1118 0.8853 0.6052 1 1 0.8606 0.8853 0.9428 0.9862 0.5383 0.2104 -0.6957 -0.8368 1 0.6052 0.6909 0.809 0.6707 0.1954 -0.4037 -0.7084 1 0.9872 0.9299 0.2604 0.1755 -0.7474 -0.711 CPI 0.897 0.8261 -0.5041 0.878 -0.1047 0.877 0.3864 -0.5514 0.2052 0.9428 0.6909 0.9872 Pers Inc 0.9349 0.857 -0.6095 0.9393 -0.0072 0.915 0.2715 -0.7062 0.339 0.9862 0.809 0.9299 0.9707 Cnsmr Conf 0.5724 0.5383 -0.7254 0.6249 0.5578 0.4702 -0.1331 -0.6963 0.5033 0.5383 0.6707 0.2604 0.3325 0.4912 Cnsmr Expt 0.3774 0.2914 -0.4463 0.2774 0.5351 0.268 0.1745 -0.1141 -0.0114 0.2104 0.1954 0.1755 0.1679 0.2056 0.7214 9 1 0.9707 0.3325 0.1679 -0.7755 -0.7662 1 0.4912 0.2056 -0.7396 -0.8315 1 0.7214 -0.1388 -0.6671 1 -0.0825 -0.3832 -0.4607 0.8572 -0.4933 0.8176 -0.5441 0.8765 -0.5548 0.9282 -0.0033 0.5157 0.3137 0.2276 FF Rate -0.8185 -0.7119 0.4645 -0.6625 -0.13 -0.8064 -0.7336 0.3413 -0.0743 -0.6957 -0.4037 -0.7474 -0.7755 -0.7396 -0.1388 -0.0825 Trade Balance -0.8714 -0.797 0.6852 1 0.8156 0.4345 -0.6009 1 0.2154 -0.7889 0.2154 1 -0.4427 -0.4427 1 -0.84 -0.3827 -0.8025 -0.272 0.6413 -0.2785 -0.8368 -0.7084 -0.711 -0.7662 -0.8315 -0.6671 -0.3832 0.6338 Ex Value USD -0.4352 -0.4955 0.3242 -0.5305 0.4352 -0.4777 0.0488 0.5733 -0.5108 -0.5596 -0.4607 -0.4933 -0.5441 -0.5548 -0.0033 0.3137 0.4345 500 Stock 0.6338 0.7468 -0.5006 0.9115 0.0489 0.7652 0.114 -0.6377 0.249 0.9541 0.8572 0.8176 0.8765 0.9282 0.5157 0.2276 -0.6009 -0.7889 From this correlation plot, the composite index of 10 leading indicators shows much higher correlation with the following individual variables than with the stock index: Average weekly hours, mfg. (hours) Manufacturers' new orders Manufacturing and trade sales Vendor performance Building permits for new private housing units (thous.) Index of stock prices, 500 common stocks, NSA (1941-43=10) Money supply, M2 (bil. chain 1992 $) Interest rate spread, 10-year Treasury bonds less federal funds Trade balance Personal savings PPI CPI Given the large number of dependent variables with such high correlations, further economic research was conducted on these indicators; we later discovered that the index of ten leading indicators actually includes many of the above variables. Most importantly, the index of leading indicators includes the TCB 500 common stock index. As a result, a second correlation plot was performed without the index of leading indicators: Variable 500 Stock 500 Avg UE Stocks Wkly Hr Claims 1 Avg Wkly 0.7468 Hr Mfrs Bldg New Permit Orders M2 Intrt Rate Spread UE Rate Capacit Mnfr & Cntrct y Util Trade & Rate Sales Orders PPI CPI Pers Inc Cnsmr Cnsmr Conf Expt FF Rate Trade Balance Ex Vendor Comd Value Prfm Prices USD 0.7468 -0.5006 0.9115 0.0489 0.7652 0.114 -0.6377 0.249 0.9541 0.8572 0.8176 0.8765 0.9282 0.5157 0.2276 -0.6009 -0.7889 -0.4427 0.0922 0.5992 1 UE Claims -0.5006 -0.812 -0.812 0.9078 0.2123 0.8006 0.3059 -0.7067 0.5284 0.8699 0.6887 0.7707 0.8261 0.857 0.5383 0.2914 -0.7119 1 -0.7392 -0.4653 -0.6496 -0.1116 0.7539 -0.6826 -0.6369 -0.6018 -0.4328 -0.5041 -0.6095 -0.7254 -0.4463 0.4645 -0.797 -0.4955 0.4503 0.6374 0.6852 0.3242 -0.575 -0.5003 Mfrs New 0.9115 0.9078 -0.7392 1 0.1647 0.8062 0.1685 -0.7852 0.5157 0.9746 0.8769 0.8053 0.878 0.9393 0.6249 0.2774 -0.6625 -0.84 -0.5305 0.3409 0.7227 Orders Bldg 0.0489 0.2123 -0.4653 0.1647 1 0.0964 0.1002 -0.1259 0.0688 0.0466 0.1329 -0.1604 -0.1047 -0.0072 0.5578 0.5351 -0.13 -0.3827 0.4352 0.4549 -0.208 Permit M2 Intrt Rate Spread 0.7652 0.8006 -0.6496 0.8062 0.0964 1 0.114 0.3059 -0.1116 0.1685 0.1002 0.4068 0.4068 -0.6457 0.2577 0.8574 0.6436 0.8492 0.877 1 UE Rate -0.6377 -0.7067 0.7539 -0.7852 -0.1259 -0.6457 0.1916 Capacity Util Rate 0.915 0.4702 0.268 -0.8064 -0.8025 -0.4777 0.1857 0.4911 0.1916 -0.2923 0.1944 -0.1141 0.4303 0.3864 0.2715 -0.1331 0.1745 -0.7336 1 0.249 0.5284 -0.6826 0.5157 0.0688 0.2577 -0.2923 -0.8275 -0.8275 -0.7427 -0.8241 -0.4541 -0.5514 -0.7062 -0.6963 -0.1141 0.3413 1 -0.272 0.0488 0.2906 -0.1127 0.6413 0.5733 -0.2084 -0.7191 0.4024 0.5588 0.1118 0.2052 0.339 0.5033 -0.0114 -0.0743 -0.2785 -0.5108 0.3459 0.6462 10 Mnfr & Trade Sales Cntrct & Orders 0.9541 0.8699 -0.6369 0.9746 0.0466 0.8574 0.1944 -0.7427 0.4024 1 0.8606 0.8853 0.9428 0.9862 0.5383 0.2104 -0.6957 -0.8368 -0.5596 0.187 0.7112 0.8572 0.6887 -0.6018 0.8769 0.1329 0.6436 -0.1141 -0.8241 0.5588 0.8606 1 0.6052 0.6909 0.809 0.6707 0.1954 -0.4037 -0.7084 -0.4607 0.1874 0.6949 PPI 0.8176 0.7707 -0.4328 0.8053 -0.1604 0.8492 0.4303 -0.4541 0.1118 0.8853 0.6052 CPI 0.8765 0.8261 -0.5041 0.878 -0.1047 0.877 0.3864 -0.5514 0.2052 0.9428 0.6909 0.9872 Pers Inc 1 0.9872 0.9299 0.2604 0.1755 -0.7474 1 0.9707 0.3325 0.1679 -0.7755 -0.7662 -0.5441 0.1159 0.6529 0.9282 0.857 -0.6095 0.9393 -0.0072 0.915 0.2715 -0.7062 0.339 0.9862 0.809 0.9299 0.9707 Cnsmr Conf Cnsmr Expt 1 0.4912 0.2056 -0.7396 -0.8315 -0.5548 0.1453 0.6813 0.5157 0.5383 -0.7254 0.6249 0.5578 0.4702 -0.1331 -0.6963 0.5033 0.5383 0.6707 0.2604 0.3325 0.4912 1 0.7214 -0.1388 -0.6671 -0.0033 0.3686 0.4724 0.2276 0.2914 -0.4463 0.2774 0.5351 0.268 0.1745 -0.1141 -0.0114 0.2104 0.1954 0.1755 0.1679 0.2056 0.7214 1 -0.0825 -0.3832 0.3137 0.3991 0.1384 FF Rate -0.6009 -0.7119 0.4645 -0.6625 -0.13 -0.8064 -0.7336 0.3413 -0.0743 -0.6957 -0.4037 -0.7474 -0.7755 -0.7396 -0.1388 -0.0825 Trade Balance Ex Value USD Vendor Prfm Comd Prices -0.7889 -0.797 0.6852 -0.711 -0.4933 0.0671 0.6231 1 -0.84 -0.3827 -0.8025 -0.272 0.6413 -0.2785 -0.8368 -0.7084 -0.711 -0.7662 -0.8315 -0.6671 -0.3832 0.6338 -0.4427 -0.4955 0.3242 -0.5305 0.4352 -0.4777 0.0488 0.5733 -0.5108 -0.5596 -0.4607 -0.4933 -0.5441 -0.5548 -0.0033 0.3137 0.4345 0.6338 0.4345 -0.2797 -0.2685 1 0.2154 -0.3013 -0.4527 0.2154 1 0.0922 0.4503 -0.575 0.3409 0.4549 0.1857 0.2906 -0.2084 0.3459 0.187 0.1874 0.0671 0.1159 0.1453 0.3686 0.3991 -0.2797 -0.3013 -0.0591 -0.0591 -0.6624 1 0.5992 0.6374 -0.5003 0.7227 -0.2018 0.4911 -0.1127 -0.7191 0.6462 0.7112 0.6949 0.6231 0.6529 0.6813 0.4724 0.1384 -0.2685 -.0.4527 -0.6624 0.1372 Based on the above grid, multicollinearity was still found among other variables, as shown by the highlighted values above. As a result, the following indicators were also removed: manufacturing new orders, manufacturing and trade sales, personal income, and PPI. The final correlation plot is shown below: Variable 500 Avg Wkly UE Hr Claims Stock Bldg Permit M2 Intrt Rate Capacity Cntrct & UE Rate Spread Util Rate Orders CPI Cnsmr Cnsmr Conf Expt FF Rate Trade Ex Value Vendor Comd Balance USD Prfm Prices 500 Stock 1 0.7468 -0.5006 0.0489 0.7652 0.114 -0.6377 0.249 0.8572 0.8765 0.5157 0.2276 -0.6009 -0.7889 -0.4427 0.0922 0.5992 Avg Wkly Hr 0.7468 1 -0.812 0.2123 0.8006 0.3059 -0.7067 0.5284 0.6887 0.8261 0.5383 0.2914 -0.7119 -0.797 -0.4955 0.4503 0.6374 UE Claims -0.5006 -0.812 1 Bldg Permit 0.0489 0.2123 -0.4653 1 M2 0.7652 0.8006 -0.6496 Intrt Rate Spread 0.114 0.3059 -0.1116 -0.6377 -0.7067 0.7539 -0.1259 -0.6457 0.1916 UE Rate Capacity Util 0.249 Rate Cntrct & 0.8572 Orders -0.4653 -0.6496 -0.1116 0.7539 -0.6826 -0.6018 -0.5041 -0.7254 -0.4463 0.4645 0.6852 0.3242 -0.575 -0.5003 0.0964 0.1002 -0.1259 0.0688 0.1329 -0.1047 0.5578 0.5351 -0.3827 0.4352 0.4549 -0.208 0.0964 1 0.4068 -0.6457 0.2577 0.6436 0.1002 0.4068 1 0.1916 -0.2923 -0.1141 0.3864 -0.1331 0.1745 -0.7336 -0.272 0.0488 1 -0.8275 -0.8241 -0.5514 -0.6963 -0.1141 0.3413 0.5733 -0.2084 -0.7191 -0.13 0.877 0.4702 0.268 -0.8064 -0.8025 0.6413 -0.4777 0.1857 0.4911 0.2906 -0.1127 0.5284 -0.6826 0.0688 0.2577 -0.2923 -0.8275 1 0.5588 0.2052 0.5033 -0.0114 -0.0743 -0.2785 -0.5108 0.3459 0.6462 0.6887 -0.6018 0.1329 0.6436 -0.1141 -0.8241 0.5588 1 0.6909 0.6707 0.1954 -0.4037 -0.7084 -0.4607 0.1874 0.6949 0.2052 0.6909 CPI 0.8765 0.8261 -0.5041 -0.1047 0.877 0.3864 -0.5514 Cnsmr Conf 0.5157 0.5383 -0.7254 0.5578 0.4702 -0.1331 -0.6963 0.5033 0.6707 0.3325 Cnsmr Expt 0.2276 0.2914 -0.4463 0.5351 0.268 0.1745 -0.1141 -0.0114 0.1954 0.1679 0.7214 -0.6009 -0.7119 0.4645 -0.8064 -0.7336 0.3413 -0.0743 -0.4037 -0.7755 -0.1388 -0.0825 0.6338 0.4345 -0.2797 -0.2685 -0.3827 -0.8025 -0.272 0.6413 -0.2785 -0.7084 -0.7662 -0.6671 -0.3832 0.6338 1 0.2154 -0.3013 -0.4527 0.2154 FF Rate Trade Balance -0.7889 -0.797 0.6852 Ex Value USD -0.4427 -0.4955 -0.13 1 0.3325 0.1679 -0.7755 -0.7662 1 0.7214 -0.1388 -0.6671 1 -0.0825 -0.3832 1 -0.5441 0.1159 0.6529 -0.0033 0.3686 0.4724 0.3137 0.3242 0.4352 -0.4777 0.0488 0.5733 -0.5108 -0.4607 -0.5441 -0.0033 0.3137 0.4345 Vendor Prfm 0.0922 0.4503 -0.575 0.4549 0.1857 0.2906 -0.2084 0.3459 0.1874 0.1159 0.3686 0.3991 -0.2797 -0.3013 -0.0591 Comd Prices 0.5992 0.6374 -0.5003 -0.208 0.4911 -0.1127 -0.7191 0.6462 0.6949 0.6529 0.4724 0.1384 -0.2685 -0.4527 -0.6624 0.1372 11 1 0.3991 0.1384 -0.0591 -0.6624 1 0.1372 1 0.1372 1 The table shows that much of the multicollinearity problem has been eliminated through the removal of five indicators: index of leading indicators, manufacturing new orders, manufacturing and trade sales, personal income, and PPI. However, it is important to realize the impossibility of completely removing multicollinearity since all of the indicators are related in some way through macroeconomic principles. Although the removal of variables will slightly diminish R2, and hence the predictability of the model, our objective is to find the best combination of the most significant and influential independent indicators in the regression model. Although considerable correlation still exists among certain variables, further removal of variables would prevent a thorough analysis of the influence of these indicators on the stock market. D. Choosing Variables With the Stepwise Regression Model After the filtering of certain variables, a stepwise regression was conducted to further narrow down the most significant indicators and to yield the highest adjusted R2 value, indicating highest predictability. The results of the first stepwise regression (Step model 1) are shown below: Response: 500 Stock Stepwise Regression Control Prob to Enter 0.250 Prob to Leave 0.250 SSE 884727.99 Lock X _ _ _ _ _ _ _ Entered X X _ X X X X X DFE 228 Direction Current Estimates MSE RSquare 3880.386 0.9472 Parameter Intercept Avg Wkly Hr UE Claims Bldg Permit M2 Intrt Rate Spread UE Rate Capacity Util Rate Estimate 2030.66465 28.4736768 ? -0.083008 -0.3213083 -32.04761 -58.964848 -29.704393 12 RSquare Adj 0.9444 nDF 1 1 1 1 1 1 1 1 Cp 9.256008 SS 0 9987.642 39.81886 27995.25 209604.7 147559.4 43864.13 121007.9 AIC 2004.185 "F Ratio" 0.000 2.574 0.010 7.215 54.016 38.027 11.304 31.184 "Prob>F" 1.0000 0.1100 0.9196 0.0078 0.0000 0.0000 0.0009 0.0000 _ _ _ _ _ _ _ _ _ X X X X X _ _ _ X Cntrct & Orders CPI Cnsmr Conf Cnsmr Expt FF Rate Trade Balance Ex Value USD Vendor Prfm Comd Prices 0.01546194 7.55712093 1.37104117 1.51430471 -19.827616 ? ? ? -4.8035508 1 1 1 1 1 1 1 1 1 388882.6 308604.9 7634.109 11304.35 88482.79 533.1804 285.0882 26.21451 124197.3 100.218 79.529 1.967 2.913 22.803 0.137 0.073 0.007 32.006 0.0000 0.0000 0.1621 0.0892 0.0000 0.7117 0.7870 0.9347 0.0000 Step History Step 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Parameter CPI Cntrct & Orders Capacity Util Rate Intrt Rate Spread Avg Wkly Hr Comd Prices M2 UE Rate Cnsmr Expt FF Rate Avg Wkly Hr Bldg Permit Avg Wkly Hr Cnsmr Conf Action Entered Entered Entered Entered Entered Entered Entered Entered Entered Entered Removed Entered Entered Entered "Sig Prob" 0.0000 0.0000 0.0000 0.0001 0.0000 0.0018 0.0159 0.0000 0.0010 0.0001 0.5487 0.0749 0.1237 0.1621 Seq SS 12866812 2028176 464129.7 91356.8 104074.3 48692.8 28276.16 93389.68 47220.86 62452.44 1431.699 12548.41 9302.653 7634.109 RSquare 0.7683 0.8894 0.9171 0.9226 0.9288 0.9317 0.9334 0.9389 0.9418 0.9455 0.9454 0.9462 0.9467 0.9472 Cp 746.62 234.53 118.88 97.728 73.348 63.005 57.838 36.166 26.197 12.367 10.73 9.549 9.1911 9.256 p 2 3 4 5 6 7 8 9 10 11 10 11 12 13 The above stepwise regression shows that much of the multicollinearity problem has been eliminated; for example, the unemployment rate now has a significant p-value, and consumer confidence and expectation are no longer negatively correlated. However, average weekly hours, consumer confidence, and consumer expectations are still included in the model even though they exhibit high p-values. A possible explanation is that their inclusion in the model contributes to a higher adjusted R2 value. After testing with various combinations of the variables, the final stepwise regression model (step model 2) is shown below: Response: 500 Stock Stepwise Regression Control Prob to Enter 0.250 Prob to Leave 0.250 SSE 914213.16 Lock Entered DFE 231 Direction Current Estimates MSE RSquare 3957.633 0.9454 Parameter Estimate 13 RSquare Adj 0.9433 nDF Cp 10.72975 SS AIC 2006.086 "F Ratio" "Prob>F" X _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ X _ _ _ X X X X X X _ X X _ _ _ X Intercept Avg Wkly Hr UE Claims Bldg Permit M2 Intrt Rate Spread UE Rate Capacity Util Rate Cntrct & Orders CPI Cnsmr Conf Cnsmr Expt FF Rate Trade Balance Ex Value USD Vendor Prfm Comd Prices 2744.42601 ? ? ? -0.3164773 -30.072942 -68.853244 -26.328913 0.01518301 8.62389599 ? 2.16589636 -15.707916 ? ? ? -4.6080835 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1431.699 1904.568 12548.41 217531.8 139643.7 109618.3 167767 482884.6 838177.3 216.337 163006.5 75646.95 0.215112 1169.58 64.92614 139365.5 0.000 0.361 0.480 3.201 54.965 35.285 27.698 42.391 122.013 211.788 0.054 41.188 19.114 0.000 0.295 0.016 35.214 Although the above model has a slightly lower adjusted R2 value than the previous stepwise model (0.9433 < 0.9444), the “entered” indicators all show highly significant pvalues of p < 0.0001. Using the set of indicators obtained from the results of the stepwise regression, the standard least squares multiple regression was performed again to create a final linear model (Model A). The regression is shown below: Response: 500 Stock Summary of Fit RSquare RSquare Adj Root Mean Square Error Mean of Response Observations (or Sum Wgts) Term Intercept M2 Intrt Rate Spre UE Rate Capacity Util R Cntrct & Orders CPI Cnsmr Expt FF Rate Comd Prices Source M2 Intrt Rate Spre Parameter Estimates Estimate 2744.426 -0.316477 -30.07294 -68.85324 -26.32891 0.015183 8.623896 2.1658964 -15.70792 -4.608083 Nparm 1 1 0.945412 0.943285 62.90972 368.508 241 Std Error 483.8281 0.042687 5.062709 13.0828 4.043872 0.001375 0.592589 0.337484 3.592863 0.776534 Effect Test DF Sum of Squares 1 217531.76 1 139643.69 14 t Ratio 5.67 -7.41 -5.94 -5.26 -6.51 11.05 14.55 6.42 -4.37 -5.93 F Ratio 54.9651 35.2847 Prob>|t| <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 Prob>F <.0001 <.0001 1.0000 0.5487 0.4891 0.0749 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.8157 0.0000 0.0000 0.9941 0.5878 0.8984 0.0000 UE Rate Capacity Util R Cntrct & Orders CPI Cnsmr Expt FF Rate Comd Prices 1 1 1 1 1 1 1 1 1 1 1 1 1 1 109618.27 167767.02 482884.62 838177.30 163006.51 75646.95 139365.53 27.6979 42.3908 122.0135 211.7875 41.1879 19.1142 35.2144 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 In this final revised model, the R2 value is 0.9454. Interestingly, three of the four “good” variables identified from the single regressions have been removed in the refinement process. Although the R2 value of our refined model is slightly less than the R2 value of 0.987 obtained in our preliminary multiple regression, we can be confident that the final combination of indicators exhibits high significance, independence, and the most influence on the TCB 500. E. Gauss-Markov Assumptions: Heteroscedasticity and Autocorrelation The Gauss-Markov Assumptions can be stated as follows: (i) εi ∼N(0, σ2), i = 1, …, n (ii) Var (εi) = σ2, i = 1, …, n (iii) (εi, . . . , εn) mutually independent If the final least squares model fits the first Gauss-Markov assumption, the residuals of the model must be normally distributed. A normal quantile plot of the residuals is shown below: 15 200 .01 .05 .10 .25 .50 .75 .90 .95 .99 150 100 50 0 -50 -100 -150 -3 -2 -1 0 1 2 3 Normal Quantile The above plot shows that the residuals are extremely close to being normally distributed; therefore, the first Gauss-Markov assumption is valid for this regression model. Next, for the new model to be accepted, possible violations of the constantvariance assumption must be tested for. The whole model test and the residual plot of the multiple regression are shown below: Whole-Model Test 1300 1100 900 800 600 500 300 100 0 -100 Source Model Error C Total 100 300 500 500 Stock 700 900 Predicted 1100 1300 Analysis of Variance DF Sum of Squares Mean Square 9 15833148 1759239 231 914213 3958 240 16747362 16 F Ratio 444.5179 Prob>F <.0001 R 150 e s 100 i d 50 u a 0 l -50 -100 -150 -100 100 300 500 500 Stock 700 900 Predicted 1100 1300 The whole model test plot shows that the data points are more scattered at higher values of the x-axis, but the variances are not significantly increasing; there are no predicted y values that terribly miss the mark. Similarly, the residual plot does not show any significant trend of increasing variance, although the residuals appear more scattered at higher values of x. Thus, the model can be accepted as fitting the constant variance assumption, meaning that the increase in values of the economic indicators does not produce overall increasing variance in the TCB 500. Although the residual plot shows no significantly discrepant values, the residuals seem to display a slightly cyclical pattern. So to test for autocorrelation in our model, the Durbin-Watson test was conducted. The results are as follows: Durbin-Watson 0.5751493 Durbin-Watson Number of Obs. 241 AutoCorrelation 0.7038 For a one-sided test at α = 0.05, the Durbin-Watson values for k = 11 and n = 200 are dL = 1.65 and dU = 1.89 (W.H. Green, Econometric Analysis). This shows that our data contains serious autocorrelation problems. This is not surprising because the data consists 17 of time series statistics that include business cycles and economic fluctuations. There are two alternatives to solving the autocorrelation problem: 1) perform a two-stage estimation procedure to modify the data by weighted differencing or 2) add additional variables which can account for the apparent autocorrelation effect. Although the second alternative is generally a superior approach, all of the x-variables used in our regressions are economic indicators and therefore unavoidably reflect business fluctuations; if we add any more of the variables that we eliminated, we would end up with our preliminary model and still not be able to correct autocorrelation. Therefore, the two-stage estimation procedure was performed, and the no-intercept regression of the residuals are shown below: Response: Residual 500 Stock Summary of Fit RSquare RSquare Adj Root Mean Square Error Mean of Response Observations (or Sum Wgts) Term Intercept Lag Residuals Source Lag Residuals Parameter Estimates Estimate Zeroed 0 0.6921693 Nparm 1 ? ? 44.27803 0.136608 240 Std Error 0 0.04757 Effect Test DF Sum of Squares 1 415083.08 t Ratio ? 14.55 F Ratio 211.7183 Prob>|t| ? <.0001 Prob>F <.0001 The estimate for p-hat is 0.692, as shown in bold. After transforming the variables, the new data set was used to run the multiple regression again (Model Atransformed). The final result is shown below: Response: T. 500 Stock Summary of Fit RSquare RSquare Adj Root Mean Square Error Mean of Response 18 0.860731 0.855281 32.79234 117.0965 Observations (or Sum Wgts) Term Intercept T.M2 T. Int Rate Spr T. UE Rate T. Cap Util Rat T. Cont & Ords T. CPI T. Cons. Expect T. FF Rate T. Comd Prices Source T.M2 T. Int Rate Spr T. UE Rate T. Cap Util Rat T. Cont & Ords T. CPI T. Cons. Expect T. FF Rate T. Comd Prices 240 Parameter Estimates Estimate 870.58837 -0.29684 -21.77922 -93.16051 -23.98903 0.0040738 10.046571 1.6722569 -10.81747 -3.875311 Nparm 1 1 1 1 1 1 1 1 1 Std Error 133.8725 0.054307 5.145625 11.11445 4.057743 0.000847 0.761136 0.317441 4.50438 1.034767 Prob>|t| <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 0.0171 0.0002 Effect Test DF Sum of Squares 1 32127.99 1 19264.29 1 75549.69 1 37583.84 1 24857.97 1 187351.23 1 29841.85 1 6201.93 1 15082.48 F Ratio 29.8771 17.9146 70.2567 34.9507 23.1164 174.2255 27.7511 5.7674 14.0258 Durbin-Watson Number of Obs. 240 AutoCorrelation 0.5008 Durbin-Watson 0.9526597 T . 1300 5 1100 800 450 0 400 0 350 S 300 t 250 900 Prob>F <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 0.0171 0.0002 Model Atransformed Model A o 600 c 500 k 300 200 150 100 50 100 0 -100 t Ratio 6.50 -5.47 -4.23 -8.38 -5.91 4.81 13.20 5.27 -2.40 -3.75 0 100 300 500 500 Stock 700 900 Predicted 1100 1300 0 19 100 200 300 T. 500 Stock Predicted 400 After the two-stage estimation, the new value of d, 0.953, is still much less than the critical value, and significant autocorrelation still exists (autocorrelation = 0.5008). However, a tradeoff must be made between the value of d and R2; while d increased from 0.692 to 0.952, R2 has dropped to 0.861 from 0.954 (Model A) in the transformed multiple regression. The whole-model test plot of the transformed regression correspondingly shows that the fit has become poorer. The federal funds rate and commodity prices also showed a large decrease in their p-values. This estimation procedure could have been carried out with more lags, but collinearity would start to become a problem since the lagged residuals are correlated with each other. The tested model therefore does not satisfy the third Gauss-Markov assumption, which states that the residual deviations are mutually independent. Because the autocorrelation problem could not be eliminated to an acceptable extent, this model would most likely not make an accurate forecasting tool. F. Predictive Abilities of the Regression Models Finally, to test the predictive abilities of our regression analyses, we used the models obtained before and after the two-stage estimation (Model A and Model Atransformed) to predict the values of the TCB 500 within the time range of our data. The actual values from WRDS and the values from both prediction models correlated very well as shown by the time series graphs below: 20 Predicted TCB 500 VS Actual TCB 500 (1977-1999) 1400 1200 1000 Predicted TCB 500 by model Real TCB 500 800 600 400 200 0 -200 time (1977-1999) Predicted Transformed TCB500 vs Actual Transformed TCB500 stocks (1977-1999) 500 400 Actual TCB 500 Predicted TCB 500 300 200 100 0 -100 time (1977-1999) We then gathered actual data on our indicators for a period outside the data range we used to derive the models. As the graph below shows, the predicted trend is terribly off the mark for the time period 1967-1977. We have found that the farther we depart from our original data range, the larger the variances. Our regression model even predicted negative values for the TCB 500! This highlights the fact that our model only works well 21 within the range of our original data and performs poorly in forecasting data outside this range. Model Prediction VS. Real TCB 500 from (1967-1977) 400 350 300 250 index value 200 Model Prediction 150 Real TCB 500 value 100 50 0 0 20 40 60 80 -50 -100 time (1967-1977) 22 100 120 140 160 IV. CONCLUSION I. Single Regression From our initial single regression plots, the four indicators that demonstrated the strongest correlation with stock price were the index of ten leading indicators, manufacturing and trade sales, CPI, and personal income. This result is not surprising: the leading indicators are a broad measure of the economy and should move in sync with the stock market; manufacturing and trade sales are a good indicator of overall economic activity and output, similar to GDP, and therefore should correspond with stock prices; the CPI measures the price level which generally increases with rising aggregate demand; and the more income an individual has, the more stocks he/she is likely to buy. II. Multiple Regression In the final multiple regression model (model A), the nine remaining economic indicators were: M2 money supply, interest rate spread, unemployment rate, capacity utilization rate, manufacturing contracts and orders, CPI, consumer expectations, the federal funds rate, and commodity prices. All of these indicators were highly significant, with p < 0.0001, and they accounted for approximately 94.5% of the variance. The model is shown again below: Response: 500 Stock Summary of Fit RSquare RSquare Adj Root Mean Square Error Mean of Response Observations (or Sum Wgts) Term Intercept M2 Parameter Estimates Estimate Std Error 2744.426 483.8281 -0.316477 0.042687 23 0.945412 0.943285 62.90972 368.508 241 t Ratio 5.67 -7.41 Prob>|t| <.0001 <.0001 Intrt Rate Spre UE Rate Capacity Util R Cntrct & Orders CPI Cnsmr Expt FF Rate Comd Prices -30.07294 -68.85324 -26.32891 0.015183 8.623896 2.1658964 -15.70792 -4.608083 5.062709 13.0828 4.043872 0.001375 0.592589 0.337484 3.592863 0.776534 -5.94 -5.26 -6.51 11.05 14.55 6.42 -4.37 -5.93 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 Based on the model, the stock market is negatively correlated with M2, interest rates, unemployment rate, commodity prices, and capacity utilization rate and positively correlated with CPI, consumer expectations, and manufacturing contracts and orders. Stock prices should be inversely related to interest rates because higher rates imply higher costs of borrowing money, and bonds would appear more attractive. Logically, the economy would be in a recession given a high unemployment rate, so these two factors are negatively related. Increases in CPI and consumer expectation generally imply growing aggregate demand and high confidence in the economy, so they are reasonably correlated with the stock index in this model. Contracts and orders for plant and equipment is a measurement of investment in the economy, and therefore correlates positively with the TCB 500 as well. However, M2 would be expected to correlate positively with stocks since it includes money market funds. In addition, higher capacity utilization rates would imply that firms are operating with higher efficiency and output, and it should have been directly correlated with stocks as well, from an economic perspective. The variables M2 and CPI should have a direct relationship as well since money supply growth leads to a proportional rise in the price level; instead, they had opposite signs. Since not all of these variables are on the same scale, their coefficients cannot be compared to evaluate the relative influence of each indicator on the stock index. However, it was surprising that indicators such as commodity prices were more 24 significant than variables such as the trade balance, which would be assumed to have bigger importance and more impact on the entire economy. Multicollinearity was substantial in our preliminary multiple regression since all the indicators are related according to economic theory; as more variables were eliminated in the refinement process, the R2 value in our model decreased slightly in return for more significant p-values and more logical coefficients. In fact, CPI was the only one of the four “quality” variables from single regression analysis to remain in the final set of indicators. This was the result of the removal of highly dependent variables. In addition, those four indicators had good polynomial fits with stock prices, but the multiple regression was based on linear relationships. While the TCB 500 stock index was predicted fairly well by our data within the same time range, it seems futile to attempt to forecast the stock market outside the range using our set of economic indicators. It is surprising that given all of the measures of economic performance that we used, a successful prediction model failed to be developed. This could be partly due to high autocorrelation problems in the model, but more importantly, it suggests that many other factors contribute to the movement of the equity market than just the economic indicators. 25 IV. SUPPLEMENTS: APPENDIX A: Single Regression Plots, TCB 500 Against All Indicators APPENDIX B: Polynomial Line Fit For Leading Indicators, Manufacturing and Trade Sales, CPI, and Personal Income APPENDIX B 500 Stock By 10 Leading Ind 1300 1100 900 800 600 500 300 100 0 90 100 10 Leading Ind Polynomial Fit degree=6 Polynomial Fit degree=6 500 Stock = 1.561e7 611383 10 Leading Ind + 6226.79 10 Leading Ind^2 + 50.4847 10 Leading Ind^3 1.47785 10 Leading Ind^4 + 0.01071 10 Leading Ind^5 0.00003 10 Leading Ind^6 Summary of Fit RSquare 0.951879 RSquare Adj 0.950645 Root Mean Square Error 58.68599 Mean of Response 368.508 Observations (or Sum Wgts) 241 Source Model Error C Total Analysis of Variance Sum of Squares Mean Square 15941455 2656909 805906 3444 16747362 DF 6 234 240 Parameter Estimates Estimate Std Error 15611913 7426678 -611383.1 391548.6 6226.7869 9018.339 50.484734 122.3188 -1.477852 1.039863 0.0107058 0.005017 -0.000026 0.00001 Term Intercept 10 Leading Ind 10 Leading Ind^2 10 Leading Ind^3 10 Leading Ind^4 10 Leading Ind^5 10 Leading Ind^6 200 100 0 -100 -200 90 100 10 Leading Ind t Ratio 2.10 -1.56 0.69 0.41 -1.42 2.13 -2.59 F Ratio 771.4502 Prob>F <.0001 Prob>|t| 0.0366 0.1198 0.4906 0.6802 0.1566 0.0339 0.0103 APPENDIX B 500 Stock By Mnfr & Trade Sales 1300 1100 900 800 600 500 300 100 0 400000 500000 600000 700000 Mnfr & Trade Sales 800000 Polynomial Fit degree=6 Polynomial Fit degree=6 500 Stock = -195090 + 2.32132 Mnfr & Trade Sales 0.00001 Mnfr & Trade Sales^2 + 2.9e-11 Mnfr & Trade Sales^3 4e-17 Mnfr & Trade Sales^4 + 2.9e-23 Mnfr & Trade Sales^5 8.9e-30 Mnfr & Trade Sales^6 Summary of Fit RSquare 0.983595 RSquare Adj 0.983174 Root Mean Square Error 34.26507 Mean of Response 368.508 Observations (or Sum Wgts) 241 Source Model Error C Total DF 6 234 240 Term Intercept Mnfr & Trade Sales Mnfr & Trade Sales^2 Mnfr & Trade Sales^3 Mnfr & Trade Sales^4 Mnfr & Trade Sales^5 Mnfr & Trade Sales^6 Analysis of Variance Sum of Squares Mean Square 16472623 2745437 274738 1174 16747362 Parameter Estimates Estimate -195090.1 2.321316 -0.000011 2.86e-11 -4.01e-17 2.945e-23 -8.87e-30 F Ratio 2338.343 Prob>F <.0001 Std Error 113131.5 1.194856 0.000005 1.2e-11 1.55e-17 1.05e-23 2.96e-30 t Ratio -1.72 1.94 -2.16 2.38 -2.59 2.80 -3.00 700000 800000 100 0 -100 400000 500000 600000 Mnfr & Trade Sales Prob>|t| 0.0859 0.0532 0.0317 0.0182 0.0101 0.0055 0.0030 APPENDIX B 500 Stock By CPI 1300 1100 900 800 600 500 300 100 0 60 70 80 90 100 120 CPI 140 160 Polynomial Fit degree=6 Polynomial Fit degree=6 500 Stock = 17244.2 1207.26 CPI + 34.3338 CPI^2 0.50537 CPI^3 + 0.00406 CPI^4 0.00002 CPI^5 + 2.85e8 CPI^6 Summary of Fit RSquare 0.989379 RSquare Adj 0.989106 Root Mean Square Error 27.57115 Mean of Response 368.508 Observations (or Sum Wgts) 241 Source Model Error C Total Analysis of Variance Sum of Squares Mean Square 16569482 2761580 177879 760 16747362 DF 6 234 240 Parameter Estimates Estimate Std Error 17244.23 16028.91 -1207.261 883.2916 34.333804 19.95 -0.505366 0.236511 0.0040617 0.001553 -0.000017 0.000005 2.8484e-8 7.6e-9 Term Intercept CPI CPI^2 CPI^3 CPI^4 CPI^5 CPI^6 t Ratio 1.08 -1.37 1.72 -2.14 2.62 -3.15 3.75 F Ratio 3632.854 Prob>F <.0001 Prob>|t| 0.2831 0.1730 0.0866 0.0337 0.0095 0.0018 0.0002 100 50 0 -50 -100 60 70 80 90 100 110 120 130 140 150 160 170 CPI APPENDIX B 500 Stock By Pers Inc 1300 1100 900 800 600 500 300 100 0 3500 4000 4500 5000 Pers Inc 5500 6000 Polynomial Fit degree=6 Polynomial Fit degree=6 500 Stock = -523578 + 733.695 Pers Inc 0.42589 Pers Inc^2 + 0.00013 Pers Inc^3 2.26e-8 Pers Inc^4 + 2.1e12 Pers Inc^5 7.8e-17 Pers Inc^6 Summary of Fit RSquare 0.986582 RSquare Adj 0.986238 Root Mean Square Error 30.98946 Mean of Response 368.508 Observations (or Sum Wgts) 241 Source Model Error C Total DF 6 234 240 Analysis of Variance Sum of Squares Mean Square 16522641 2753773 224721 960 16747362 Parameter Estimates Estimate Std Error -523578.5 194766.6 733.69489 266.0705 -0.425889 0.150455 0.0001311 0.000045 -2.256e-8 7.548e-9 2.059e-12 6.7e-13 -7.78e-17 2.46e-17 Term Intercept Pers Inc Pers Inc^2 Pers Inc^3 Pers Inc^4 Pers Inc^5 Pers Inc^6 t Ratio -2.69 2.76 -2.83 2.91 -2.99 3.08 -3.16 F Ratio 2867.479 Prob>F <.0001 Prob>|t| 0.0077 0.0063 0.0050 0.0040 0.0031 0.0024 0.0018 100 50 0 -50 -100 3500 4000 4500 Pers Inc 5000 5500 6000
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