155S1.2_3 Statisitcal Thinking
January 10, 2012
MAT 155
Section 1­2 Statistical Thinking
Dr. Claude Moore
Cape Fear Community College
Key Concept
Chapter 1
This section introduces basic principles of statistical thinking used throughout this book. Whether conducting statistical analysis of data that we have collected, or analyzing a statistical analysis done by someone else, we should not rely on blind acceptance of mathematical calculation. Introduction to Statistics
1­1 Review and Preview
1­2 Statistical Thinking
1­3 Types of Data
1­4 Critical Thinking
1­5 Collecting Sample Data
Section 1­2 Statistical Thinking
Key Concept (continued)
We should consider these five (5) factors:
1. Context of the data
2. Source of the data
3. Sampling method
4. Conclusions
5. Practical implications
Section 1­2 Statistical Thinking
1. Context of Data
What do the values represent?
Where did the data come from?
Why were they collected?
An understanding of the context will directly affect the statistical procedure used.
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155S1.2_3 Statisitcal Thinking
January 10, 2012
Section 1­2 Statistical Thinking
2. Source of Data
Is the source objective?
Is the source biased?
Is there some incentive to distort or spin results to support some self­serving position?
Is there something to gain or lose by distorting results?
Section 1­2 Statistical Thinking
3. Sampling Method
Does the method chosen greatly influence the validity of the conclusion?
Voluntary response ﴾or self­
selected﴿ samples often have bias ﴾those with special interest are more likely to participate﴿. Section 1­2 Statistical Thinking
Section 1­2 Statistical Thinking
5. Practical Implications
State practical implications of the results.
4. Conclusions
Make statements that are clear to those without an understanding of statistics and its terminology.
Avoid making statements not There may exist some statistical significance yet there may be NO practical significance.
Common sense might suggest that the finding does not make enough of a difference to justify its use or to be practical.
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155S1.2_3 Statisitcal Thinking
January 10, 2012
Section 1­2 Statistical Thinking
Section 1­2 Statistical Thinking
Statistical Significance
Consider the likelihood of getting the results by chance.
In Exercises 7–14, use common sense to determine whether the given event is (a) impossible; (b) possible, but very unlikely; (c) possible and likely.
9/8. While driving to his home in Connecticut, David Letterman was ticketed for driving 205 mi/h on a highway with a speed limit of 55 mi/h. If results could easily occur by chance, then they are not statistically significant.
If the likelihood of getting the results is so small, then the results are statistically significant.
9/12. Calculators When each of 25 statistics students turns on his or her TI­ 84 Plus calculator, all 25 calculators operate successfully.
10/16. In Exercises 15–18, refer to the data in the table below. The x­values are nicotine amounts (in mg) in different 100 mm filtered, non­“ light” menthol cigarettes; the y­values are nicotine amounts (in mg) in different king­size nonfiltered, nonmenthol, and non­“ light” cigarettes. ( The values are from Data Set 4 in Appendix B.)
10/20. Conclusion Given the context of the car measurement data, what issue can be addressed by conducting a statistical analysis of the values? 3