Correlation Analysis and Simple Linear Regression

Correlation Analysis and Simple Linear Regression

472. Which one of the following statements is always true?

(A) The greater the value of the correlation coefficient, the stronger is

the relationship.

(B) A strong positive correlation between two variables means one of

the variables causes the effect of the other variable.

(C) If two variables are independent, their correlation does not exist.

(D) Pearson product-moment correlation coefficients numerically

quantify only linear relationships.

Chapter 13

1323 ❯ McGraw-Hill’s 500 Statistics Questions

473. Which one of the following scatterplots shows the strongest linear relationship between variables X and Y ?

(A)

Variable X

Variable Y

(B)

Variable X

Variable Y

(C)

Variable X

Variable Y

(D)

Variable X

Variable Y

Correlation Analysis and Simple Linear Regression

Correlation Analysis and Simple Linear Regression ❮ 133

474. Which one of the following statements comparing correlation coefficients

is true?

(A) 0.40 is stronger than 0.75.

(B) -0.50 is stronger than -0.95.

(C) 0.82 is weaker than 0.68.

(D) -0.54 is equal in strength to 0.54.

475. The following correlation table shows the correlations between pairs of

variables from among the four variables W, X, Y, and Z.

Correlation Table for Variables W, X, Y, and Z

Variable W Variable X Variable Y Variable Z

Variable W 1

Variable X -0.85 1

Variable Y 0.47 0.82 1

Variable Z -0.58 0.60 -0.79 1

The correlation coefficient between which of the following pairs of variables

shows the strongest relationship?

(A) W and X

(B) Y and W

(C) X and Y

(D) Y and Z

476. A biologist is interested in the relationship between age (in years) and

the maximum pulse rate (in beats per minute) for women. A sample of

five women yielded the following five pairs of data. Calculate the sample

product-moment correlation coefficient r by formula. (Round your answer,

as needed.)

Woman 1 Woman 2 Woman 3 Woman 4 Woman 5

Age x (years) 20 39 18 44 50

Pulse rate y (beats

per minute)

210 180 200 165 120

(A) r = -0.904

(B) r = -0.749

(C) r = 0.904

(D) r = 0.749

1345 ❯ McGraw-Hill’s 500 Statistics Questions

477. The following data give the number of hours each of six students in a statistics class spent studying and each student’s corresponding score (out of

100 points) on the final exam. Using a graphing calculator, calculate the

product-moment correlation coefficient r for the sample. (Round your

answer, as needed.)

Student Number 1 2 3 4 5 6

Study time x (in hours) 1.50 2.75 3.00 4.50 5.75 6.00

Score on exam y 54 73 70 82 91 89

(A) r = -0.969

(B) r = -0.939

(C) r = 0.939

(D) r = 0.969

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