1. The farther the points on a scatter diagram from the regression line, the _________ between the scores.

a. higher the correlation

b. lower the correlation

c. correlation doesn't change

d. need more information

___ 2. The strongest correlation shown below is _________.

a. 0.75

b. -0.33

c. -0.25

d. 0.15

____ 3. When deciding which measure of correlation to employ with a specific set of data, you should consider _________.

a. whether the relationship is linear or nonlinear

b. type of scale of measurement for each variable

c. a and b

d. none of the above

____ 4. Which of the following statements concerning Pearson r is not true?

a. r = 0.00 represents the absence of a relationship.

b. The relationship between the two variables must be nonlinear.

c. r = 0.76 has the same predictive power as r = -0.76.

d. r = 1.00 represents a perfect relationship.

e. All of the above are true statements.

__

__ 5. Spearman’s Rho is used _________.

a. when both variables are dichotomous

b. when both variables are of interval or ratio scaling

c. when one or both variables are only of ordinal scaling

d. when the data is nonlinear

____ 6. When a correlation exists, lowering the range of either of the variables will _________.

a. raise the correlation

b. lower the correlation

c. not change the correlation

d. produce a causal relationship

___ 7. If two variables are ratio scaled and the relationship is linear, what type of correlation coefficient is most appropriate?

a. Pearson

b. Spearman

c. eta

d. phi

____ 8. You have conducted a brilliant study which correlates IQ score with income and find a value of r = 0.75. At the end of the study you find out all the IQ scores were scored 10 points too high. What will the value of r be with the corrected data?

a. r will be increased

b. r will be decreased

c. r will remain the same

d. cannot be determined

____ 9. If 49% of the total variability of Y is accounted for by X, what is the value of r?

a. 0.49

b. 0.51

c. 0.70

d. 0.30

____ 10. Satisfying the assumption of homoscedasticity allows you to _________.

a. Interpret the standard error of estimate

b. Calculate multiple R

c. Calculate a standardized regression coefficient

d. Decide who has been naughty or nice

11. For the following X and Y scores, how much of the variability of Y is accounted for by knowledge of X? Assume a linear relationship.

X 20 15 6 10

Y 6 5 4 0

a. 68%

b.34%

c. 58%

d. 27%

12. Which of the following values of r represents the strongest degree of relationship between two variables?

a. 0.55

b. 0.00

c. 0.78

d. 0.80

13. After several studies, Professor Smith concludes that there is a zero correlation between body weight and bad tempers. This means that _________.

a. heavy people tend to have bad tempers

b. skinny people tend to have bad tempers

c. no one has a bad temper

d. everyone has a bad temper

e. a person with a bad temper may be heavy or skinny

14. The closer the points on a scatter diagram fall to the regression line, the _________ between the scores.

a. higher the correlation

b. lower the correlation

c. correlation doesn't change

d. need more information

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