6.Telephone CallsA researcher knew that before cell phones, a person made on average2.6calls per day. He believes that the number of calls made per day today is higher. He selects a random sample of29individuals who use a cell phone and asks them to keep track of the number of calls that they made on a certain day. The mean was2.9. At=0.05, is there enough evidence to support the researcher's claim? The standard deviation for the population found by a previous study is0.8. Assume that the variable is normally distributed. Use theP-value method with tables.

State the hypotheses and identify the claim.

H0: =2.6

not claim

H1: >2.6claim

The hypothesis test is aone-tailedtest.

Compute the test value. Always round

zscore values to at least two decimal places.z =?

7.Daily Driving The average number of miles a person drives per day is 24. A researcher wishes to see if people over age 60 drive less than 24 miles per day. She selects a random sample of 34 drivers over the age of 60 and finds that the mean number of miles driven is 22.3. The population standard deviation is 3.4 miles. At =0.05, is there sufficient evidence that those drivers over 60 years old drive less than 24 miles per day on average? Assume that the variable is normally distributed. Use the P-value method with tables.

State the hypotheses and identify the claim.

H0: =24not claim

H1: <24claim

The hypothesis test is aone-tailedtest.

Compute the test value. Always roundzscore values to at least two decimal places.z=?

8.Weight Loss of Newborns An obstetrician read that a newborn baby loses on average 7 ounces in the first two days of his or her life. He feels that in the hospital where he works, the average weight loss of a newborn baby is less than 7 ounces. A random sample of 35 newborn babies has a mean weight loss of 6.8 ounces. The population standard deviation is 1.3 ounces. Is there enough evidence at =0.01 to support his claim? Assume that the variable is normally distributed. Use the P-value method with tables.

State the hypotheses and identify the claim.

H0: =7 not claim

H1: <7 claim

The hypothesis test is a one-tailedtest.

Compute the test value. Always round z score values to at least two decimal places. z=?

9.Dress Shirts In a previous study conducted several years ago, a man owned on average 14 dress shirts. The standard deviation of the population is 3. A researcher wishes to see if that average has changed. He selected a random sample of 39 men and found that the average number of dress shirts that they owned was 13.7. At =0.05, is there enough evidence to support the claim that the average has changed? Assume that the variable is normally distributed. Use the P-value method with tables.

State the hypotheses and identify the claim.

H0: =14 not claim

H1: 14 claim

The hypothesis test is a two-tailedtest.

Compute the test value. Always round z score values to at least two decimal places. z= ?

10.Breaking Strength of Cable A special cable has an average breaking strength of 800 pounds. The standard deviation of the population is 12 pounds. A researcher selects a sample of 22 cables and finds that the average breaking strength is 792 pounds. Can he reject the claim that the breaking strength is 800 pounds? Use the P-value method with =0.10 level of significance. Assume that the variable is normally distributed.

State the hypotheses and identify the claim.

H0: =800 claim

H1: 800 not claim

The hypothesis test is a two-tailedtest.

Compute the test value. Always round z score values to at least two decimal places. z=?