Question

Assume that it is appropriate and meaningful to calculate the correlation coefficient of two variables X and Y. If the correlation coefficient, r, has a value -0.95

Select one:

a. it is impossible to tell if there is a linearly relationship between the two variables

b. there is a strong linear relationship between the two variables

c. there is no relationship between the two variables

d. the slope of the regression line will be -0.95

2.

The father's height (in inches) and the (adult) son's height (in inches) are linearly associated. In a sample of 100 father-and-son pairs, the correlation coefficient, r, was found to be 0.8. If the height measurements of the father's and the son's are changed to centimetre (cm), what will be the new correlation coefficient ? (Note: one inch =2.54 cm)

Select one:

a. The answer cannot be calculated due to not enough information

b. 0.8

c.

d.

3.

Beer and Blood Alcohol Content

The relationship between number of beers consumed (x) and blood alcohol content ( y) was studied in 25 male college students by using simple linear regression. The estimated blood alcohol content ( ŷ ) is given in the following regression equation:

ŷ = -0.0127 + 0.0180x

The above equation estimates that:

Select one:

a. each beer consumed increases blood alcohol content by 0.0127

b. on average each beer consumed increases blood alcohol content by 0.0307

c. on average each beer consumed increases blood alcohol content by 0.0180

d. on average each beer consumed increases blood alcohol content by 0.0153

e. on average it takes 0.0180 beers to increase blood alcohol content by 0.0127

4.

Beer and Blood Alcohol Content

The relationship between number of beers consumed (x) and blood alcohol content ( y) was studied in 25 male college students by using simple linear regression. The estimated blood alcohol content ( ŷ ) is given in the following regression equation:

ŷ = -0.0127 + 0.0180x

Suppose that the legal blood alcohol content limit for driving is 0.05. If John consumed 4 beers the model would predict that he would be:

Select one:

a. 0.0027 above the legal limit

b. 0.0347 above the legal limit

c. 0.0093 above the legal limit

d. 0.022 above the legal limit

e. 0.0027 below the legal limit

5.  

A multiple choice test has 12 questions. Each question has 4 choices of which exactly one is correct. If a student makes random guesses for all 12 questions, what is the probability that the student will get exactly 5 questions correct?

Select one:

a. The answer cannot be determined from the given information.

b. 0.2270

c. 0.0584

d. 0.1032

e. 0.0532

6.

A medical doctor knows from past experience that 80% of his patients have private health insurance and 20% do not have private insurance. He also notices that among those who have private health insurance, 65% are over the age of 50 while among those who do not have private health insurance, only 30% are over the age of 50. What is the probability that a randomly selected patient is over 50 years of age and has private health insurance?

Select one:

a. 0.65

b. 0.3

c. 0.52

d. 0.16

e. The answer cannot be determined from the given information.

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Answer 1

1

Assume that it is appropriate and meaningful to calculate the correlation coefficient of two variables X and Y. If the correlation coefficient, r, has a value -0.95

Answer : b. there is a strong linear relationship between the two variables

2.

The father's height (in inches) and the (adult) son's height (in inches) are linearly associated. In a sample of 100 father-and-son pairs, the correlation coefficient, r, was found to be 0.8. If the height measurements of the father's and the son's are changed to centimetre (cm), what will be the new correlation coefficient ?

Answer : b. 0.8

3.

Beer and Blood Alcohol Content

The relationship between number of beers consumed (x) and blood alcohol content ( y) was studied in 25 male college students by using simple linear regression. The estimated blood alcohol content ( ŷ ) is given in the following regression equation:

ŷ = -0.0127 + 0.0180x

The above equation estimates that:

Answer e. on average it takes 0.0180 beers to increase blood alcohol content by 0.0127