A Statistics professor has observed that for several years students score an average of 108 points out of 150 on the semester exam. A salesman suggests that he try a statistics software package that gets students more involved with? computers, predicting that it will increase? students' scores. The software is? expensive, and the salesman offers to let the professor use it for a semester to see if the scores on the final exam increase significantly. The professor will have to pay for the software only if he chooses to continue using it. In the trial course that used this? software,

201201

students scored an average of

111111

points on the final with a standard deviation of

8.98.9

points. Complete parts? a) and? b) below.

?a) Should the professor spend the money for this? software? Support this recommendation with an appropriate test. Use

alpha?equals=0.05.

What are the null and alternative? hypotheses?

Upper H 0H0?:

?

?

nothing

Upper H Subscript Upper AHA?:

?

?

less than<

greater than>

equals=

not equals?

nothing

What is the test? statistic?

?

z

t

equals=nothing

?(Round to two decimal places as? needed.)

What is the? P-value?

?P-valueequals=nothing

?(Round to four decimal places as? needed.)

What is the appropriate? conclusion?

A.

Fail to reject

Upper H 0H0.

The change is statistically significant. The software does appear to improve exam scores.

B.

Reject

Upper H 0H0.

The change is not statistically significant. The software does not appear to improve exam scores.

C.

Reject

Upper H 0H0.

The change is statistically significant. The software does appear to improve exam scores.

D.

Fail to reject

Upper H 0H0.

The change is not statistically significant. The software does not appear to improve exam scores.

?b) Does this improvement seem to be practically? significant? Choose the correct answer below and fill in any answer boxes within your choice.

?(Round to one decimal place as? needed.)

A.

No. A? 95% confidence interval for the mean score using the software is

left parenthesis nothing comma nothing right parenthesis,.

?Students' scores improved by no more than 5 points on the exam. This might not be enough to justify the cost.

B.

Yes. A? 95% confidence interval for the mean score using the software is

left parenthesis nothing comma nothing right parenthesis,.

?Students' scores improved by at least 5 points on the exam. These improvements may be worth the cost of the software.

C.

No. A? 95% confidence interval for the mean score using the software is

left parenthesis nothing comma nothing right parenthesis,.

The change is not statistically significant.? Students' scores may not improve at all in the long run. The software is not worth the cost.