A computer laboratory manager was in charge of purchasing ne

A computer laboratory manager was in charge of purchasing new battery packs for her lab of laptop computers. She narrowed her choices to two models that were available for her machines. Since the models cost about the same, she was interested in determining whether there was a difference in the average time the battery packs would function before needing to be recharged. She took two independent samples and computed the following summary information:

Battery Pack Model 1

Battery Pack Model 2

Sample Size

9

9

Sample Mean

5 hours

5.5 hours

Standard Deviation

1.5 hours

1.3 hours

Using the following null and alternate hypothesis:
H0:mu1-mu2=0 vs. Ha:mu1-mu2 not equal 0
Test statistic is t=-0.7557
Assume alpha = 0.05 what is the appropriate conclusion for this test?

A.Reject H0

B.Reject Ha

C.none of these

D.Do not reject H0

Solution

for alpha = 0.05

alpha / 2 = 0.025

df = 9-1= 8

critcal value : 2.306

we fail to reject Ho ( do not reject Ho)