Question

Ten randomly selected people took an IQ test A, and next day they took a very similar IQ test B. Their scores are shown in the table below. Person A B C D E F G H I J Test A 113 107 112 85 97 103 94 71 125 89 Test B 120 107 114 88 97 103 93 74 124 94 1. Consider (Test A - Test B). Use a 0.05 significance level to test the claim that people do better on the second test than they do on the first. (Note: You may wish to use software.) (a) What test method should be used? A. Two Sample t B. Two Sample z C. Matched Pairs (b) The test statistic is (c) The critical value is (d) Is there sufficient evidence to support the claim that people do better on the second test? A. No B. Yes 2. Construct a 95% confidence interval for the mean of the differences. Again, use (Test A - Test B). <μ

Answer 1

a)

C. Matched Pairs

b)

test statistic t =-2.1083 (please take care of number of decimals)

c)

critical value t =-1.8331 (please take care of number of decimals)

d)

Yes

e)

for 95% CI; and 9 degree of freedom, value of t=			2.262
therefore confidence interval=sample mean -/+ t*std error
margin of errror          =t*std error=		1.931
lower confidence limit                     =		-3.7313
upper confidence limit                    =		0.1313
from above 95% confidence interval for population mean =(-3.731,0.131)