8. An investigator is interested in predicting scores for a measure of cognitive function from the number of hours of sleep a person gets on average. She obtains scores for both the number of hours of sleep and cognitive function from 12 people. Higher scores for cognitive function reflect higher levels of performance.

Hours of Sleep

8.1

5.4

6.1

7.4

9.0

8.5

6.4

9.4

8.7

7.6

9.3

9.2

Cognitive Function

100

79

72

62

122

89

76

131

110

92

101

115

a.Compute the correlation coefficient (r) of number of hours of sleep and cognitive function.

b.Is there a significant linear correlation between number of hours of sleep and cognitive function? Use

c.Fit the linear regression equation that expresses cognitive function (y) in terms of number of hours of sleep.

d.Interpret and

e.Compute and interpret

f.Find the best predicted cognitive function of someone with a number of hours of sleep of 10 hours.