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 106 90 119 111 77 95 100 83 102 127

Test B 107 89 124 114 79 97 100 83 106 130

1. Consider (Test A - Test B). Use a 0.01 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.)

(1)The test statistic is

(2) Construct a 99% confidence interval for the mean of the differences. Again, use (Test A - Test B).

<μ

Answer 1

1)

test statistic =-3.143

2)

for 99% CI; and 9 degree of freedom, value of t=			3.250
therefore confidence interval=sample mean -/+ t*std error
margin of errror          =t*std error=		1.965
lower confidence limit                     =		-3.8649
upper confidence limit                    =		0.0649
from above 99% confidence interval for population mean =(-3.86 <μ < 0.06)