A coffee manufacturer is interested in whether the mean daily consumption of regular-coffee drinkers is less than that of decaffeinated-coffee drinkers. Assume the population standard deviation for those drinking regular coffee is 1.29 cups per day and 1.44 cups per day for those drinking decaffeinated coffee. A random sample of 55 regular-coffee drinkers showed a mean of 4.41 cups per day. A sample of 47 decaffeinated-coffee drinkers showed a mean of 5.16 cups per day.

Use the 0.01 significance level.

a.Is this a one-tailed or a two-tailed test?

multiple choice 1

One-tailed test.

Two-tailed test.

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

c.Compute the value of the test statistic.(Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.)

As part of a study of corporate employees, the director of human resources for PNC Inc. wants to compare the distance traveled to work by employees at its office in downtown Cincinnati with the distance for those in downtown Pittsburgh. A sample of 35 Cincinnati employees showed they travel a mean of 370 miles per month. A sample of 40 Pittsburgh employees showed they travel a mean of 380 miles per month. The population standard deviations for the Cincinnati and Pittsburgh employees are 30 and 26 miles, respectively. At the 0.05 significance level, is there a difference in the mean number of miles traveled per month between Cincinnati and Pittsburgh employees?

a.Is this a one-tailed or a two-tailed test?

multiple choice 1

One-tailed test

Two-tailed test

b.State the decision rule.(Negative values should be indicated by a minus sign. Round your answers to 2 decimal places.)

c.Compute the value of the test statistic.(Negative value should be indicated by a minus sign. Round your answer to 2 decimal places.)

d.What is your decision regardingH₀?

multiple choice 2

Not rejectedH₀

RejectedH₀

e.Is there a difference in the mean number of miles traveled per month between Cincinnati and Pittsburgh employees?

multiple choice 3

Yes

No

The Tampa Bay (Florida) Area Chamber of Commerce wanted to know whether the mean weekly salary of nurses was larger than that of school teachers. To investigate, they collected the following information on the amounts earned last week by a sample of school teachers and nurses.

School Teachers ($)

1,095

1,076

1,077

1,125

1,034

1,059

1,052

1,070

1,079

1,080

1,092

1,082

Nurses ($)

1,091

1,140

1,071

1,021

1,100

1,109

1,075

1,079

Is it reasonable to conclude that the mean weekly salary of nurses is higher? Use the 0.01 significance level.Hint:For the calculations, assume the nurses as the first sample.

Click here for the Excel Data File

a.Is this a one-tailed or a two-tailed test?

multiple choice 1

One-tailed test

Two-tailed test

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

A coffee manufacturer is interested in whether the mean daily consumption of regular-coffee drinkers is less than that of decaffeinated-coffee drinkers. Assume the population standard deviation for those drinking regular coffee is 1.20 cups per day and 1.36 cups per day for those drinking decaffeinated coffee. A random sample of 50 regular-coffee drinkers showed a mean of 4.35 cups per day. A sample of 40 decaffeinated-coffee drinkers showed a mean of 5.84 cups per day.

Use the 0.01 significance level.

a.Is this a one-tailed or a two-tailed test?

multiple choice 1

One-tailed test.

Two-tailed test.

b.State the decision rule.(Negative values should be indicated by a minus sign. Round your answer to 2 decimal places.)

c.Compute the value of the test statistic.(Negative value should be indicated by a minus sign. Round your answer to 2 decimal places.)

d.What is thep-value ?

e.What is your decision regardingH₀?

multiple choice 2

RejectH₀.

Do not rejectH₀.

The president of the American Insurance Institute wants to compare the yearly costs of auto insurance offered by two leading companies. He selects a sample of 15 families, some with only a single insured driver, others with several teenage drivers, and pays each family a stipend to contact the two companies and ask for a price quote. To make the data comparable, certain features, such as the deductible amount and limits of liability, are standardized. The data for the sample of families and their two insurance quotes are reported below.

At the 0.10 significance level, can we conclude that there is a difference in the amounts quoted? Hint: For the calculations, assume the "Midstates Car Insurance" as the first sample.

Midstates Car Gecko Mutual

FamilyInsurance Insurance

Becker$2,090 $1,610

Berry 1,683 1,247

Cobb 1,402 2,327

Debuck 1,830 1,367

DuBrul 930 1,461

Eckroate 697 1,789

German 1,741 1,621

Glasson 1,129 1,914

King 1,018 1,956

Kucic 1,881 1,772

Meredith 1,571 1,375

Obeid 874 1,527

Price 1,579 1,767

Phillips 1,577 1,636

Tresize 860 1,188

Click here for the Excel Data File

State the decision rule for 0.10 significance level: H0: d = 0H1: d 0. (Negative values should be indicated by a minus sign. Round your answers to 3 decimal places.)

Compute the test statistic. (Negative value should be indicated by a minus sign. Round your answer to 2 decimal places.)

State your decision about the null hypothesis.

multiple choice

Do not reject H0

Reject H0