You want to buy a washing machine, and a salesperson tells you that the mean repair costs for Model A and Model B are equal. You research the repair costs. The mean repair cost of 25 Model A washing machines is $209. Assume the population standard deviation is $17. The mean repair cost of 20 Model B washing machines is $218. Assume the population standard deviation is $20. At =0.01, can you reject the salesperson's claim? Assume the samples are random and independent, and the populations are normally distributed.

Complete parts (a) through (e).

(a) Identify the claim and state

H0 and Ha.

What is the claim?

A.

The mean repair cost for Model A is less than Model B.

B.

The mean repair costs for Model A and Model B are equal.

C.

The mean repair costs for Model A and Model B are different.

D.

The mean repair cost for Model A is greater than Model B.

Let 1 be the mean repair cost for Model A and let 2 be the mean repair cost for Model B. What are H0 and Ha?

A.

H0:

1=2

Ha:

12

B.

H0:

12

Ha:

1<2

C.

H0:

12

Ha:

1>2

D.

H0:

12

Ha:

1=2

E.

H0:

1>2

Ha:

12

F.

H0:

1<2

Ha:

12

(b) Find the critical value(s) and identify the rejection region(s).

The critical value(s) is/are =?

(Round to two decimal places as needed. Use a comma to separate answers as needed.)

What is/are the rejection region(s)?

Select the correct choice below and fill in the answer box(es) within your choice.

(Round to two decimal places as needed.)

A.

z< ?

z> ?

B.

z

C.

z>enter your response here

(c) Find the standardized test statistic z for

12.

z=enter your response here

(Round to two decimal places as needed.)

(d) Decide whether to reject or fail to reject the null hypothesis. Choose the correct answer below.

A.

Fail to reject

H0.

The standardized test statistic

is

in a rejection region.

B.

Reject

H0.

The standardized test statistic

is not

in a rejection region.

C.

Reject

H0.

The standardized test statistic

is

in a rejection region.

D.

Fail to reject

H0.

The standardized test statistic

is not

in a rejection region.

(e) Interpret the decision in the context of the original claim.

At the

enter your response here%

significance level, there is

insufficient

sufficient

evidence to

support

reject

the claim that the mean repair costs for Model A are

less than

different from

greater than

equal to

the mean repair costs for Model B.