1.

Consider the hypothesis statement to the right. State your conclusion given that s=2.2, n=25, and =0.10.

H0: 29.0 H1: 2<9.0

Calculate the appropriate test statistic.

The test statistic is=

(Round to two decimal places as needed.)

Determine the appropriate critical value(s).

The critical value(s) is(are)=

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

Conclusion-

(reject or not reject) the null hypothesis. There is (sufficient, insufficient) evidence that the population variance is

(different from, less than, greater than) 9.0.

2.

Consider the hypothesis statement to the right. State your conclusion given that s=2.5, n=30, and =0.05.

H0: 23.0 H1: 2>3.0

Calculate the appropriate test statistic.

The test statistic is=

(Round to two decimal places as needed.)

Determine the appropriate critical value(s).

The critical value(s) is(are)=

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

Conclusion-

(Reject, Do not reject) the null hypothesis. There is (insufficient, sufficient) evidence that the population variance is

(less than, greater than, different from) 3.0.

3.

Consider the hypothesis statement to the right. State your conclusion given that s=7.5, n=30, and =0.05.

H0: 2=38.0 H1: 238.0

Calculate the appropriate test statistic.The test statistic is

enter your response here.

(Round to two decimal places as needed.)Determine the appropriate critical value(s).The critical value(s) is(are)

enter your response here.

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

State your conclusion.

(Do not reject, Reject) the null hypothesis. There is (sufficient, insufficient) evidence that the population variance is (equal to, different from) 38.0.

4. Recently, a pizza place was receiving complaints about erratic pizza delivery times. To address this issue, the owners made some operational changes in its restaurant and added more delivery people to its staff. To study these changes, the owners would like to test the hypothesis that the standard deviation for the delivery times of its pizza is less than

18 minutes. The data shown to the right represent a random sample of delivery times (in minutes). Complete parts a and

b.

22	39	13
35	29	39
35	16	28
35	15	10
12	11	11

a. Using =0.10, test whether or not the pizza place's goal was achieved.

Identify the null and alternative hypotheses.

H0: 2(less than<, greater than>, not equals) then #

H1: 2(less than<, greater than>, not equals) then #

(Type integers or decimals.)

Calculate the appropriate test statistic.

The test statistic is=

(Round to two decimal places as needed.)

Determine the appropriate critical value(s).

The critical value(s) is(are)=

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

State your conclusion.

Since the test statistic is (greater than, between, less than) the(upper critical value, critical values, critical value, lower critical value,) (do not reject, reject) the null hypothesis. There is (insufficient, sufficient) evidence that the standard deviation is(equal to, not equal to, greater than, less than)18 minutes.

b. Use technology to find the p-value and interpret the result.The p-value is

enter your response here.

(Round to three decimal places as needed.)

Since the p-value is (less than, greater than) , (do not reject, reject) the null hypothesis. There is (sufficient, insufficient) evidence to conclude that the standard deviation is (not equal to, equal to, less than, greater than) 18 minutes.

5. Identify the appropriate critical F-score for n1=12, n2=11, and =0.01.

The critical F-score is

=

(Round to three decimal places as needed.)

6. (right tail distribution)(formatting explained)

Consider the hypothesis statement shown.

H0: 21=22 (2 should be directly over 1) (2 should be directly over 2)

H1: 2122 (2 should be directly over 1) (2 should be directly over 2)

State your conclusion given that

s1=30, s2=28, n1=24, n2=29, and =0.05

a. Calculate the appropriate test statistic.

The test statistic is=

(Round to two decimal places as needed.)

Determine the appropriate critical value(s).

The critical value(s) is(are)=

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

b. Conclusion

(Do not reject, Reject) the null hypothesis. There is (sufficient, insufficient) evidence that the population variances are different.

7. (right tail distribution)(formatting explained)

Consider the hypothesis statement shown below.

H0: 21=22 (2 should be directly over 1) (2 should be directly over 2)

H1: 2122 (2 should be directly over 1) (2 should be directly over 2)

State your conclusion given that

s1=59, s2=42, n1=20, n2=24, and =0.05.

Calculate the appropriate test statistic.The test statistic is

enter your response here.

(Round to two decimal places as needed.)Determine the appropriate critical value(s).The critical value(s) is(are)

enter your response here.

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

Conclusion-

(Do not reject, Reject) the null hypothesis. There is(insufficient, sufficient) evidence that the population variances are different.

8. Security is investigating procedures at an airport to reduce the variability in the amount of time it takes passengers to get through airport security. The following table summarizes sample data collected from two different terminals employing different security procedures. Complete parts a and b.

Terminal A- Sample standard deviation-8.1 Sample size- 13

Terminal B- Sample standard deviation-8.9 Sample size- 12

a. Using =0.05, determine if the procedures at Terminal A more effectively reduce the variability than do the procedures at Terminal B. First identify the hypotheses. Choose the correct answer below.

(2 should be over 1 ) and (2 should be over 2)

A.

H0:

2122

H1:

21=22

B.

H0:

21=22

H1:

2122

C.

H0:

2122

H1:

21<22

D.

H0:

2122

H1:

21>22

Calculate the appropriate test statistic.

The test statistic is=

(Round to two decimal places as needed.)

Determine the appropriate critical value(s).

The critical value(s) is(are)=

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

Conclusion-

(Reject, Do not reject) the null hypothesis. There is (sufficient, insufficient) evidence to conclude that the procedures at Terminal A more effectively reduce the variability than do the procedures at Terminal B.

b. Use technology to find the p-value and interpret the result.

The p-value is=

(Round to three decimal places as needed.)

Since the p-value is(greater than, less than)=0.05, (do not reject, reject)the null hypothesis. There is (insufficient, sufficient) evidence to conclude that the procedures at Terminal A more effectively reduce the variability than do the procedures at Terminal B.

9. A teacher's union would like to see if there is a difference in the variability of the salaries earned by high school teachers in one county as compared to another. A random sample of teacher salaries from each county was selected, and the standard deviation of each sample was calculated. Use the information given below to complete parts a and b.

	County 1	County 2
Sample standard deviation	$4,000	$3,300
Sample size	25	25

a. Using =0.10, determine if there is a difference in the variability of the salaries in the two counties. Identify the null and alternative hypotheses. (2 should be over 1) (2 should be over 2)

H0:21(equals=, greater than or equals, less than or equals)22

H1:21(less than<, greater than>, not equals)22

Calculate the appropriate test statistic.

The test statistic is=

(Round to two decimal places as needed.)

Determine the appropriate critical value(s).

The critical value(s) is(are)=

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

Conclusion-

(Do not reject, Reject) the null hypothesis. There is (sufficient, insufficient) evidence that the population variance for County 1 is (greater than, different from, less than, equal to) the population variance for County 2.

b. Use technology to find the p-value and interpret the result.

The p-value is

=

(Round to three decimal places as needed.)

Conclusion-

Since the p-value is (less than, greater than) =0.10,(reject, do not reject) the null hypothesis. There is (sufficient, insufficient) evidence to conclude that the population variance for County 1 (differs from, equals, is less than, is greater than)County 2.

10. Low-profile tires are automobile tires that have a short sidewall height, which is the distance between the tire rim and the road. These tires provide better performance at the expense of gas mileage. A car model was chosen to measure the effect these tires have on the variability of the car's gas mileage. Ten cars of this model were selected, and the gas mileage each obtained on one tank of gas was measured using standard tires. Low-profile tires were installed on 10 other cars, and the gas mileage was again recorded. Use the information given below to complete parts a and b.

Standard(S) LowProfile(LP)

S LP

21.4 21.4 22.2 19.9 25.2 23.2 18.9 19.3 21.6 21.3 25.8 18.7 24.7 19.4 18.6 15.4 23.7 20.7 22.5 22.1

a. Using

=0.05,

determine if there is a difference in the variability of the mileage the two types of tires get.Let

21

represent the larger sample variance and let

22

represent the smaller sample variance. Identify the null and alternative hypotheses.

H0:

21

less than or equals

equals=

greater than or equals

22

H1:

21

not equals

less than<

greater than>

22

Calculate the appropriate test statistic.The test statistic is

enter your response here.

(Round to two decimal places as needed.)Determine the appropriate critical value(s).The critical value(s) is(are)

enter your response here.

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

Determine if there is a difference in the variability of the mileage the two types of tires get by finishing the conclusion-

(Do not reject, Reject) the null hypothesis. There is (insufficient, sufficient) evidence that the population variance for the mileage of standard tires is (equal to, less than, greater than, different from)the population variance for the mileage of low-profile tires.

b. Interpret the p-value.The p-value is

enter your response here.

(Round to three decimal places as needed.)

Use the p-value to draw a conclusion.

Since the p-value is (less than, greater than) =0.05,(reject, do not reject)the null hypothesis. There is (sufficient, insufficient)evidence that the population variance for the mileage of standard tires(equals, differs from, is less than, is greater than) the population variance for the mileage of low-profile tires.

11. An insurance company would like to investigate if the average number of miles driven per month by a male teenage driver exceeds the average number of miles driven per month by a female teenage driver. The following data summarizes the sample statistics for the miles driven per month by each gender. Use the information given below to complete parts a and b.

	Male	Female
Sample mean	687	578
Sample size	24	29
Sample standard deviation	148	101

a. Recall that testing for a difference between two population means requires an assumption about population variances. Perform a hypothesis test using =0.10 to determine if the population variance for miles driven per month is different for teenage males and teenage females. Let 21 represent the larger sample variance and let 22

represent the smaller sample variance.

Identify the null and alternative hypotheses:

H0:21(less than or equals, equals=, greater than or equals)22

H1: 21(greater than>, less than<, not equals)22

Calculate the appropriate test statistic.

The test statistic is=

(Round to two decimal places as needed.)

Determine the appropriate critical value(s).

The critical value(s) is(are)=

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

Determine if there is a difference in the variances.

(Reject, Do not reject) the null hypothesis. There is (sufficient, insufficient) evidence that the population variance for the miles driven per month for teenage males is(greater than, different from, equal to, less than) the population variance for the miles driven per month for teenage females.

b. Identify the p-value and interpret the results.

The p-value is=

(Round to three decimal places as needed.)

Use the p-value to draw a conclusion.

Since the p-value is(less than, greater than) =0.10,(do not reject, reject) the null hypothesis. There is sufficient, insufficient) evidence that the population variance for the miles driven per month for teenage males (differs from, is greater than, equals, is less than) the population variance for the miles driven per month for teenage females.