A study was done on proctored and nonproctored tests. The results are shown in the table. Assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Complete parts (a) and (b) below. Use a 0.050.05

significance level for both parts.

Proctored

Nonproctored

mu

mu 11

mu 22

n

3030

3434

x overbarx

78.0178.01

83.8483.84

s

11.0111.01

21.5921.59

a. Test the claim that students taking nonproctored tests get a higher mean score than those taking proctored tests.

What are the null and alternative hypotheses?

A.

Upper H 0H0:

mu 11equals=mu 22

Upper H 1H1:

mu 11less than<mu 22

B.

Upper H 0H0:

mu 11equals=mu 22

Upper H 1H1:

mu 11not equalsmu 22

C.

Upper H 0H0:

mu 11not equalsmu 22

Upper H 1H1:

mu 11less than<mu 22

D.

Upper H 0H0:

mu 11equals=mu 22

Upper H 1H1:

mu 11greater than>mu 22

The test statistic, t, is nothing .

(Round to two decimal places as needed.)

The P-value is nothing .

(Round to three decimal places as needed.)

State the conclusion for the test.

State the conclusion for the test.

A.

RejectReject

Upper H 0H0.

There isis

sufficient evidence to support the claim that students taking nonproctored tests get a higher mean score than those taking proctored tests.

B.

Fail to rejectFailtoreject

Upper H 0H0.

There is notisnot

sufficient evidence to support the claim that students taking nonproctored tests get a higher mean score than those taking proctored tests.

C.

RejectReject

Upper H 0H0.

There is notisnot

sufficient evidence to support the claim that students taking nonproctored tests get a higher mean score than those taking proctored tests.

D.

Fail to rejectFailtoreject

Upper H 0H0.

There isis

sufficient evidence to support the claim that students taking nonproctored tests get a higher mean score than those taking proctored tests.

b. Construct a confidence interval suitable for testing the claim that students taking nonproctored tests get a higher mean score than those taking proctored tests.

nothing less than<mu 1 minus mu 212less than

(Round to three decimal places as needed.)

Does the confidence interval support the conclusion of the test?

Yes,

No,

because the confidence interval contains

zero.

only negative values.

only positive values.