A home power-washing business is interested between the relationship between the square footage of a home (X, in 1000s ft2) and the time to complete the job (Y, in hours). Records from n=18 past homes have been sampled, and a simple linear regression model is fit. The following quantities are obtained:

18. Give the predicted time to power-wash a 2500 ft2 home.

a) 2.3 hours b) 1200.2 hours c) 2.0 hours d) 1.1 hours e) 2000.3 hours

19. Labelling your previous answer as T, a 95% confidence interval for the mean time to wash all 2000 ft2 homes, and a 95% prediction interval for tomorrow morning’s washing of a 2000 ft2 house are T:

A

B

C

D

E

CI:

0.117772

0.316017

0.149071

0.790042

0.904934

PI:

0.316017

0.904934

0.965734

0.426875

2.262336

20.

Your manager brings you the following computer output, and asks you to explain to him in words what the results are. What is the best response (at the =0.05 significance level), considering it represents sample information from 5 segments of individuals?

Contingency Table

Segment

Accept

Decline

TOTAL

A

20

80

100

B

40

60

100

C

25

75

100

D

50

50

100

E

15

85

100

TOTAL

150

350

500

chi-squared Stat

40.4762

df

4

p-value

0

chi-squared Critical

9.4877

a)

Conclude mean #of acceptances differ by individuals in segments A-E

b)

Cannot conclude mean # of acceptances differ by individuals in segments A-E