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Name: February 27, 2001 Score:

MATH 147

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Quiz 5

(4 pts.)

Problem 1. Circle T for a true statement, F for a false statement.

T F The regression line is a smooth version of the graph of averages.

T F The correlation coefficient can not distinguish between association and causation.

T F If you discover that your scatter diagram shows a nonlinear pattern, it is okay to use linear regression for predictions as long as you do not extrapolate.

T F Ecological correlations tend to understate the strength of association for individuals.

(6 pts.)

Problem 2. A statistical analysis of first year GPA's and SAT scores is taken by a university admissions office. The scatter diagram of the data is football shaped. A summary of the data is:

Average GPA = 2.3 with an SD = .5.

Average SAT = 1025 with an SD = 150. r = 0.8

Predict the first year GPA of an applicant.

Predict the first year GPA of an applicant that scored 1100 on the SAT.