1. Assume that you have a sample of n1=8, with the sample mean X1=47, and a sample standard deviation of

S1=4, and you have an independent sample of n2=15 from another population with a sample mean of X2=34, and the sample standard deviation S2=6. Construct a99% confidence interval estimate of the population mean difference between 1 and 2.

Assume that the two population variances are equal.

_______12______

(Round to two decimal places as needed.)

2. Assume that you have a sample of n1=8, with the sample mean X1=47, and a sample standard deviation of S1=5,

and you have an independent sample of n2=4 from another population with a sample mean of X2=32 and the sample standard deviation S2=6. Assuming the population variances are equal, at the 0.01 level of significance, is there evidence that 1>2?

Determine the hypotheses. Choose the correct answer below.

A. H0: 12

H1: 1>2

B. H0: 12

H1: 1=2

C. H0: 1=2

H1: 12

D. H0: 1>2

H1: 12

Find the test statistic.

tSTAT=______

(Round to two decimal places as needed.)

Find the p-value.

p-value=_______

(Round to three decimal places as needed.)

Choose the correct conclusion below.

a. Reject H0. There is insufficient evidence that u1>u2

b. Reject H0. There is sufficient evidence that u1?u2

c. Do not reject H0. There is sufficient evidence that u1>u2

d. Do not reject H0. There is insufficient evidence that u1>u2.

3. An experimental design for a paired t test has 11 pairs of identical twins. How many degrees of freedom are there in this

ttest?

There are ______degrees of freedom.

(Simplify your answer.)

4. An experimental design for a paired t test has 11 pairs of identical twins. How many degrees of freedom are there in this t test?

There are________degrees of freedom.

(Simplify your answer.)