ame: ________________________ Class: ___________________ Date: __________
Statistics Practice 1
Multiple Choice
Identify the choice that best completes the statement or answers the question.
Find the mean, median, and mode of the data set. Round to the nearest tenth.
____
____
____
1. 2, 1, 13, 9, 10, 6, 15, 9, 1, 13, 13
a. mean = 7.7,
b. mean = 8.4,
c. mean = 7.7,
d. mean = 8.4,
median = 9,
median = 8,
median = 9,
median = 9,
mode = 13
mode =13
mode = 8
mode = 13
2. test scores on a math exam:
83, 86, 77, 82, 93, 79, 98, 72, 73, 95, 70, 83, 89, 84, 82, 70, 75, 89, 86, 89, 74, 97
a. mean = 83,
b. mean = 76.1,
c. mean = 83,
d. mean = 76.1,
median = 84,
median = 83,
median = 83,
median = 83,
mode = 89
mode = 89
mode = 89
mode = 84
3. A set of data ____ has one and only one mode.
a. always
b. sometimes
c. never
Find the values of the 30th and 90th percentiles of the data.
____
____
4. 18, 9, 7, 5, 11, 7, 17, 20, 19, 2, 17, 12, 5, 1, 13, 12, 11, 15, 16, 20
a. 30th percentile = 9;
c. 30th percentile = 11;
90th percentile = 20
90th percentile = 19
b. 30th percentile = 9;
d. 30th percentile = 7;
90th percentile = 19
90th percentile = 20
5. In this set of data, at what percentile is 10? At what percentile is 18?
10, 10, 10, 12, 14, 16, 16, 18, 18, 18
a. 10 is at the 10th percentile;
c. 10 is at the 30th percentile;
18 is at the 80th percentile.
18 is at the 90th percentile.
b. 10 is at the 20th percentile;
d. 10 is at the 0th percentile;
18 is at the 100th percentile.
18 is at the 70th percentile.
Find the outlier in the set of data.
____
6. 6.3, 0.4, 5.3, 3.1, 5.4, 5.6, 5.8, 4.4
a. 5.4
b. 5.6
c.
0.4
d.
5.3
Find the range and interquartile range of the data. Round to the nearest tenth.
____
7. 235, 131, 136, 107, 144, 255, 330
a. range = 199; interquartile range = 111
b. range = 223; interquartile range = 124
c.
d.
1
range = 223; interquartile range = 111
range = 199; interquartile range = 124
ID: A
ame: ________________________
____
____
ID: A
8. Another measure of variation is variance, which equals σ 2 . Find the variance and standard deviation of the
data set. Round to the nearest tenth.
6, 4, 11, 7, 7, 12
a. variance = 7.8;
c. variance = 1.7;
standard deviation = 3.1
standard deviation = 3.1
b. variance = 1.7;
d. variance = 7.8;
standard deviation = 2.8
standard deviation = 2.8
9. Susan keeps track of the number of tickets sold for each play presented at The Community Theater. Within
how many standard deviations of the mean do all the values fall?
115, 125, 164, 79, 88, 82, 108, 121, 148, 92, 66, 101
a. 2
b. 1
c. 5
d. 3
Determine whether the situation calls for a survey, an observational study, an experiment, or nothing.
____ 10. You want to find out if years of lifting heavy weights has an affect on flexibility.
a. observational study
c. survey
b. nothing
d. experiment
____ 11. The table shows the prices (in dollars) of the latest models of cars of different motor companies.
20,000
20,000
25,000
30,000
32,000
35,000
40,000
40,000
40,000
48,000
Find the mean, median, and mode of the prices.
a.
b.
34,000, 35,000, and 40,000
34,545.45, 40,000, and 40,000
c.
d.
34,545.45, 35,000, and 40,000
34,545.45, 35,000, and 20,000
Find the variance and standard deviation of the given set of data to the nearest tenth.
____ 12. {520, 130, 260, 450, 200, 680, 790}
a. variance = 53,191.8, standard deviation = 230.6
b. variance = 230.6, standard deviation = 53,191.8
c. variance = 53,191.8, standard deviation = 26,595.9
d. variance = 62,057.1, standard deviation = 249.1
2
50,000
ame: ________________________
ID: A
____ 13. Identify the outlier in the data set {42, 13, 23, 24, 5, 5, 13, 8}, and determine how the outlier affects the
mean, median, and mode of the data.
a.
Without outlier
mean = 13
median = 13
modes = 5, 13
With outlier
mean = 16.6
median = 13
modes = 5, 13
The outlier is 42. The outlier increases the mean by 3.6. The outlier has no effect on the
median and the modes.
b.
Without outlier
mean = 13
median = 13
modes = 5, 13
With outlier
mean = 13
median = 16.6
modes = 5, 13
The outlier is 42. The outlier increases the median by 3.6. The outlier has no effect on
the mean and the modes.
c.
Without outlier
mean = 13
median = 13
modes = 5, 13
With outlier
mean = 16.6
median = 18
modes = 5, 13
The outlier is 42. The outlier increases the mean by 3.6 and the median by 5. The outlier
has no effect on the modes.
d.
Without outlier
mean = 11.4
median = 13
modes = 5, 13
With outlier
mean = 16.6
median = 13
modes = 5, 13
The outlier is 42. The outlier increases the mean by 5.2. The outlier has no effect on the
median and the modes.
____ 14. The monthly rents for five apartments advertised in a newspaper were $660, $660, $760, $1800, and $830.
Use the mean, median, and mode of the rents to answer the question. Which value best describes the monthly
rents? Explain.
mean = $942, median = $760, mode = $660
a.
b.
c.
The mean best describes the rents because $942 is the average rent.
The median best describes the rents because most of the rents were near $ 760.
The mode best describes the rents because $660 was the rent seen most often.
3
ame: ________________________
ID: A
____ 15. Suppose that the numbers of students in Algebra 1 classes in the United States are approximately normally
distributed. The list gives the numbers of students in 10 classes.
24, 24, 32, 15, 21, 34, 20, 27, 19, 28
Find the mean and standard deviation of the data set. Then sketch a normal curve to represent the
distribution.
a.
mean = 27; standard deviation = 5.6
b.
mean = 24.4; standard deviation = 31.8
c.
mean = 27; standard deviation = 31.8
d.
mean = 24.4; standard deviation = 5.6
____ 16. A researcher surveys people at a train station about whether they favor a tax increase to improve railroad
service. Explain why the following statement is misleading: “75% of commuters support a railroad tax
increase.”
a.
b.
c.
d.
The sample is biased because train riders are more likely to favor better railroad service
than commuters who drive or use other types of transportation.
The sample is biased because the researcher did not say how large the tax increase would
be.
The statement is misleading because not enough people were surveyed.
The data includes outliers, so the mean percentage is not a fair measure.
4
ame: ________________________
ID: A
The weights of 870 young deer tagged and weighed in a research study are normally distributed with a
mean of 78 pounds and a standard deviation of 2.5 pounds.
____ 17. Approximately how many deer weigh more than 83 pounds?
a. 22 deer
c. 23 deer
b. 44 deer
d. 20 deer
____ 18. What percent of deer weigh between 73 and 80.5 pounds? Round your answer to the nearest integer.
a. 82%
c. 47%
b. 80%
d. 50%
____ 19. Suppose a store manager wants to know the demand y for an energy bar as a function of price x. The daily
sales of three different energy bars (different prices) are shown in the table. Use the regression capabilities of
a graphing calculator to find the least squares regression line for the data.
Price, x
$1.29
$1.49
$1.69
Demand, y
550
495
470
a.
b.
y8 = −197x + 806
y8 = −200x + 803
c.
d.
y8 = −190x + 806
y8 = −200x + 753
____ 20. Suppose an agronomist used four test plots to determine the relationship between the wheat yield y (in
bushels per acre) and the amount of fertilizer x (in hundreds of pounds per acre), used for the yield. The
results are shown in the table. Find the least squares regression line for the data using the regression
capabilities of a graphing calculator. Then use this model to estimate the yield for a fertilizer application of
160 pounds per acre. Round off your answer to one decimal place.
Fertilizer, x
1.0
1.5
2.0
2.5
Yield, y
32
42
50
56
a.
b.
y8 = 19x + 20; 47.0 bushels per acre
y8 = 26x + 20; 56.0 bushels per acre
c.
d.
5
y8 = 16x + 17; 39.0 bushels per acre
y8 = 16x + 12; 34.0 bushels per acre
ID: A
Statistics Practice 1
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
D
C
B
A
D
C
B
D
D
A
C
A
A
B
D
A
A
A
B
C
1