This learning activity consists of a variety of problems from Chapters 13–15. Spaces for answers are provided; please type your answers directly in the document. Consider highlighting, starring*, or changing the font color of answers for ease of instructor grading.

1. (20 Pts, 1 Pt each). Calculate the mean, median, mode, standard deviation, and range for the following sets of measurements (fill out the table):

a. 13, 7, 6, 6, 3

b. 14, 12, 11, 10, 8

c. 65, 65, 65, 65, 65

d. 12, 10, 9, 8, 6, 51

2. (20 Pts, 5 pts each) Answer the following questions.

a. Why is the SD in (d) so large compared to the SD in (b)?

b. Why is the mean so much higher in (d) than in (b)?

c. Why is the median relatively unaffected?

d. Which measure of central tendency best represents the set of scores in (d)? Why?

3. (24 pts, 2 pts each) Fill in the blanks on the table with the appropriate raw scores, z-scores, T-scores, and __approximate__ percentile ranks. You may refer to the distribution curve below.

4. (20 pts, 2 pts each) The Graduate Record Exam (GRE) has a combined verbal and quantitative mean of 1000 and a standard deviation of 200. Scores range from 200 to 1600 and are approximately normally distributed. For each of the following problems:

(a) Indicate the percentage or score called for by the problem.

(b) Select the appropriate distribution curve (from below) that relates to the problem.

**a.** What percentage of the persons who take the test score below 800? _____

Type the curve __best__ representing your answer: _____

**b.** Above what score do the top 6.68% of the test-takers score? _____

Type the curve __best__ representing your answer: _____

**c.** Above what score do 84.13% of the test-takers score? _____

Type the curve __best__ representing your answer: _____

**d.** What percentage of the persons who take the test score above 1168? _____

Type the curve __best__ representing your answer: _____

**e.** What percentage of the persons who take the test score below 1200? _____

Type the curve __best__ representing your answer: _____

5. (16 pts, varied) Refer to the following data and scatterplots to respond to questions 5a-5f.

__Individual__

__Age__

__Score on Popular Music Test__

Figure A represents a scatterplot constructed from the data; Figure B represents a regression line drawn through the scatterplot that “fits” the data points reasonably well; Figure C represents an ellipse drawn around the data points.

a. (2 pts.) Estimate the direction of the correlation:

b. (2 pts.) Estimate the strength of the correlation coefficient:

Consider Figure D (below).

c. (2 pts.) Using only the data points associated with age of 50 and above; what effect does this have on the __direction__ and __strength__ of the correlation coefficient?

d. (4 pts.) Explain why this is the case.

e. (2 pts.) Explain in words what a truncated scatterplot means.

f. (4 pts.) Identify how likely it is that a causal relationship has been indicated.