Statistics

Statistics

Appendices

Appendix A: Homework Sets

A.1 Homework Set: Summarizing, Organizing, and Describing Data

Z-score Practice

1. If an IQ test has a mean of 100 and a standard deviation of 15, find the corresponding z score for each IQ. a. a. 115 b. 122 c. 93 d. 100 e. 85

2. Which of the following exam grades has a better relative position, (a) or (b)? a. A grade of 43 on a test with mean = 40 and s =3. b. A grade of 75 on a test with mean= 72 and s = 5.

Percentile Practice

3. Data Set: 5, 12, 15, 16, 20, and 21

a. Find the percentile rank for each test score in the data set. b. What test score corresponds to the 33rd percentile?

Scatter Plots

4. A researcher wishes to determine if a person’s age is related to the number of hours he or she exercises per week. The data for the sample are shown here.

Age, x

18 10

26

32

38

52 1.5

59

Hours, y

5

2

3

1

a. Draw a scatter plot (Graph paper is good, but if you don’t have any just do a simple x- axis and y-axis and that will work). Intervals of 1 on the x-axis. Intervals of 5 on the y- axis. Just suggestions. b. Describe the data. Is it positive or negative, or no correlation?

5. Give examples of two variables that are positively correlated and two that are negatively correlated.

Order of Operations

Evaluate the expressions for problems 6-10.

6. 3- 4+5 7. 100-(-50)-75 8. 10 – (-5)

9. -15+5 10. -16+5(2)

Answer key is found on page 86.

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