Statistics Works sheets

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problem_set_iii.docx

1.

value: 10.00 points

 

A sample of 32 observations is selected from a normal population. The sample mean is 32, and the population standard deviation is 6. Conduct the following test of hypothesis using the 0.05 significance level.

  

H0 : μ ≤ 29

H1 : μ > 29

 

a.

Is this a one- or two-tailed test?

 

 

 

"One-tailed"-the alternate hypothesis is greater than direction.

"Two-tailed"-the alternate hypothesis is different from direction.

 

b.

What is the decision rule? (Round your answer to 3 decimal places.)

 

   H0, when z > 

 

c.

What is the value of the test statistic? (Round your answer to 2 decimal places.)

 

  Value of the test statistic

  

 

d.

What is your decision regarding H0?

 

 

 

Reject

Do not reject

 

There is  evidence to conclude that the population mean is greater than 29.

 

e.

What is the p-value? (Round your answer to 4 decimal places.)

 

  p-value

    

 2.

value: 10.00 points

 

At the time she was hired as a server at the Grumney Family Restaurant, Beth Brigden was told, “You can average $71 a day in tips.” Assume the population of daily tips is normally distributed with a standard deviation of $4.48. Over the first 33 days she was employed at the restaurant, the mean daily amount of her tips was $73.33. At the 0.05 significance level, can Ms. Brigden conclude that her daily tips average more than $71?

  

a.

State the null hypothesis and the alternate hypothesis.

 

 

 

H0: μ ≤ 71 ; H1: μ > 71

H0: μ ≥ 71 ; H1: μ < 71

H0: μ >71 ; H1: μ = 71

H0: μ = 71 ; H1: μ ≠ 71

  

b.

State the decision rule.

 

 

 

Reject H1 if z > 1.65

Reject H1 if z < 1.65

Reject H0 if z > 1.65

Reject H0 if z < 1.65

  

c.

Compute the value of the test statistic. (Round your answer to 2 decimal places.)

  

  Value of the test statistic

  

  

d.

What is your decision regarding H0?

 

 

 

Do not reject H0

Reject H0

   

e.

What is the p-value? (Round your answer to 4 decimal places.)

  

  p-value

  

3.

value: 10.00 points

 

The Rocky Mountain district sales manager of Rath Publishing Inc., a college textbook publishing company, claims that the sales representatives make an average of 37 sales calls per week on professors. Several reps say that this estimate is too low. To investigate, a random sample of 43 sales representatives reveals that the mean number of calls made last week was 38. The standard deviation of the sample is 2.6 calls. Using the 0.010 significance level, can we conclude that the mean number of calls per salesperson per week is more than 37?

     

H0 : μ ≤ 37

H1 : μ > 37

  

1.

Compute the value of the test statistic. (Round your answer to 3 decimal places.)

  

  Value of the test statistic

  

  

2.

What is your decision regarding H0?

  

   H0. The mean number of calls is  than 37 per week.

4.

value: 10.00 points

 

A United Nations report shows the mean family income for Mexican migrants to the United States is $26,450 per year. A FLOC (Farm Labor Organizing Committee) evaluation of 23 Mexican family units reveals a mean to be $37,190 with a sample standard deviation of $10,700. Does this information disagree with the United Nations report? Apply the 0.01 significance level.

a.

State the null hypothesis and the alternate hypothesis.

 

 

  H0: μ =

  

  H1: μ ≠

  

b.

State the decision rule for .01 significance level. (Negative amounts should be indicated by a minus sign. Round your answers to 3 decimal places.)

  Reject H0 if t is not between  and 

c.

Compute the value of the test statistic. (Round your answer to 2 decimal places.)

  Value of the test statistic

  

d.

Does this information disagree with the United Nations report? Apply the 0.01 significance level.

  . This data  the report.

5.

value: 10.00 points

 

The following information is available.

 

H0 : μ ≥ 220

 

H1 : μ < 220

 

A sample of 64 observations is selected from a normal population. The sample mean is 215, and the population standard deviation is 15. Conduct the following test of hypothesis using the .025 significance level.

 

a.

Is this a one- or two-tailed test?

 

 

 

One-tailed test

Two-tailed test

 

b.

What is the decision rule? (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.)

 

   H0 when z <    

 

c.

What is the value of the test statistic? (Negative amount should be indicated by a minus sign. Round your answer to 3 decimal places.)

 

  Value of the test statistic

  

 

d.

What is your decision regarding H0?

 

 

 

Reject

Do not reject

 

e.

What is the p-value? (Round your answer to 4 decimal places.)

 

  p-value

  

6.

value: 10.00 points

 

Given the following hypotheses:

 

H0 : μ ≤ 10

H1 : μ > 10

 

A random sample of 10 observations is selected from a normal population. The sample mean was 12 and the sample standard deviation 3. Using the .05 significance level:

 

a.

State the decision rule. (Round your answer to 3 decimal places.)

 

  Reject H0 if t >

  

 

b.

Compute the value of the test statistic. (Round your answer to 3 decimal places.)

 

  Value of the test statistic

  

 

c.

What is your decision regarding the null hypothesis?

 

 

 H0. There is  evidence to conclude that the population mean is greater than 10.  

7.

value: 10.00 points

 

Given the following hypotheses:

 

H0 : μ = 400

 

H1 : μ ≠ 400

 

A random sample of 12 observations is selected from a normal population. The sample mean was 407 and the sample standard deviation 6. Using the .01 significance level:

 

a.

State the decision rule. (Negative amount should be indicated by a minus sign. Round your answers to 3 decimal places.)

 

  Reject H0 when the test statistic is  the interval (,  ).

 

b.

Compute the value of the test statistic. (Round your answer to 3 decimal places.)

 

  Value of the test statistic

  

 

c.

What is your decision regarding the null hypothesis?

 

 

 

Reject

Do not reject

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