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Guidelines for the Jolly Blue Giant Health Insurance Company say that the averag

ID: 3371487 • Letter: G

Question

Guidelines for the Jolly Blue Giant Health Insurance Company say that the average hospitalization for a triple hernia operation should not exceed 30 hours. A diligent auditor studied records of 16 randomly chosen triple hernia operations at Hackmore Hospital, and found a mean hospital stay of 40 hours with a standard deviation of 20 hours. "Aha!" she cried, "the average stay exceeds the guideline." The p-value for a right-tailed test of her hypothesis is:

less than .01.

between .025 and .05.

between .01 and .025.

between .05 and .10.

Explanation / Answer

Sol:

H0:mu=30

H1:mu>30

alpha=0.05

t=sample mean-pop mean/sample sd/sqrt(n

=40-30/20/sqrt(16)

=10/2

t=2

df=n-1=16-1=15

p=0.032

P<0.05

between .025 and .05.

OPTION B