Question

The Central Limit Theorem holds.

The following table gives pre and post test scores for boys and girls in a drivers ed class.

Boys Pre-Test	Boys Post Test	Girls Pre-Test	Girls Post Test
45	63	55	75
57	75	62	88
71	82	66	85
66	90	59	93
62	92	72	70
58	78	69	93
63	94	70	89
60	90
64	74

Try to show the boys pre-test population mean is significantly less than 65. Let = .05.

Hypotheses, Test Statistic, Diagram & p-value, and Decision.

Answer 1

Sol:

Ho:

Ha:

alpha=0.05

For the given sample of pretest boys 63 75 82 90 92 78 94 90 74

sample mean=xbar=82

sample standard deviation= 10.38027

sample size=n=9

t=xbar-mu/s/sqrt(n)

=(82-65)/(10.38027/sqrt(9))

= 4.913167

df=n-1=9-1=8

P value in excel

==T.DIST( 4.913167,9,TRUE)

=0.999583799

p>0.05

Fail to reject Ho

Accept Ho

Cocnlcsion:

There is suffcient statistical evidence at 5% level of significnace to conclude that the pre-test population mean is significantly less than 65.