# statistical analysis

2.5 Points

##### Question 1 of 40
2.5 Points
A two-tailed test is conducted at the 5% significance level. What is the left tail percentile required to reject the null hypothesis?

 A. 97.5% B. 5% C. 2.5% D. 95%
##### Question 2 of 40
2.5 Points

A consumer group claims that the mean running time for a certain type of flashlight battery is not the same as the manufacturer’s claims. Determine the null and alternative hypotheses for the test described.

 A. H0: µ = Manufacturer’s claims     Ha: µ < Manufacturer’s claims B.    H0: µ = Manufacturer’s claims    Ha: µ ¹ Manufacturer’s claims C. H0: µ = Manufacturer’s claims     Ha: µ > Manufacturer’s claims D. H0: µ ¹ Manufacturer’s claims     Ha: µ = Manufacturer’s claims
##### Question 3 of 40
2.5 Points
The owner of a football team claims that the average attendance at home games is over 4000, and he is therefore justified in moving the team to a city with a larger stadium. Assume that a hypothesis test of the claim has been conducted and that the conclusion of the test was to reject the null hypothesis. Identify the population to which the results of the test apply.

 A. All games played by the team in question in which the attendance is over 4000 B. All future home games to be played by the team in question C. All home games played by the team in question D. None of the populations given are appropriate
##### Question 4 of 40
2.5 Points
A right-tailed test is conducted at the 5% significance level. Which of the following z-scores is the smallest one in absolute value that leads to rejection of the null hypothesis?

 A. 1.61 B. 1.85 C. -1.98 D. -2.06
##### Question 5 of 40
2.5 Points

In 1990, the average duration of long-distance telephone calls originating in one town was 9.4 minutes. A long-distance telephone company wants to perform a hypothesis test to determine whether the average duration of long-distance phone calls has changed from the 1990 mean of 9.4 minutes. The mean duration for a random sample of 50 calls originating in the town was 8.6 minutes. Does the data provide sufficient evidence to conclude that the mean call duration, µ, is different from the 1990 mean of 9.4 minutes? Perform the appropriate hypothesis test using a significance level of 0.01. Assume that s = 4.8 minutes.

 A. With a z of -1.2 there is sufficient evidence to conclude that the mean value has changed from the 1990 mean of 9.4 minutes. B. With a P-value of 0.2302 there is not sufficient evidence to conclude that the mean value is less than the 1990 mean of 9.4 minutes. C. With a P-value of 0.2302 there is sufficient evidence to conclude that the mean value is less than the 1990 mean of 9.4 minutes. D. With a z of –1.2 there is not sufficient evidence to conclude that the mean value has changed from the 1990 mean of 9.4 minutes.
##### Question 6 of 40
2.5 Points

A study of a brand of “in the shell peanuts” gives the following results:

A significant event at the 0.01 level is a fan getting a bag with how many peanuts?

 A. 30 peanuts B. 25 or 30 peanuts C. 25 or 55 peanuts D. 25 peanuts
##### Question 7 of 40
2.5 Points

A manufacturer claims that the mean amount of juice in its 16 ounce bottles is 16.1 ounces. A consumer advocacy group wants to perform a hypothesis test to determine whether the mean amount is actually less than this. The mean volume of juice for a random sample of 70 bottles was 15.94 ounces. Do the data provide sufficient evidence to conclude that the mean amount of juice for all 16-ounce bottles, µ, is less than 16.1 ounces? Perform the appropriate hypothesis test using a significance level of 0.10. Assume that s = 0.9 ounces.

 A.    The z of – 1.49    provides sufficient evidence to conclude that the mean amount of juice is less than 16.1 oz. B. The z of – 1.49 does not provide sufficient evidence to conclude that the mean amount of juice is less than 16.1 oz. C. The z of – 0.1778 does not provide sufficient evidence to conclude that the mean amount of juice is less than 16.1 oz. D. The z of – 0.1778 provides sufficient evidence to conclude that the mean amount of juice is less than 16.1 oz.
##### Question 8 of 40
2.5 Points
A two-tailed test is conducted at the 0.10 significance level. What is the P-value required to reject the null hypothesis?

 A. Greater than or equal to .010 B. Greater than or equal to 0.05 C. Less than or equal to 0.10 D. Less than or equal to 0.05
##### Question 9 of 40
2.5 Points
A researcher claims that the amounts of acetaminophen in a certain brand of cold tablets have a mean different from the 600 mg claimed by the manufacturer. Test this claim at the 0.02 level of significance. The mean acetaminophen content for a random sample of n = 41 tablets is 603.3 mg. Assume that the population standard deviation is 4.9 mg.

 A. Since the test statistic is greater than the critical z, there is sufficient evidence to accept the null hypothesis and to support the claim that the mean content of acetaminophen is 600 mg. B. Since the test statistic is greater than the critical z, there is sufficient evidence to reject the null hypothesis and to support the claim that the mean content of acetaminophen is not 600 mg. C. Since the test statistic is less than the critical z, there is sufficient evidence to reject the null hypothesis and to support the claim that the mean content of acetaminophen is not 600 mg. D. Since the test statistic is greater than the critical z, there is insufficient evidence to reject the null hypothesis and to support the claim that the mean content of acetaminophen is not 600 mg.
##### Question 10 of 40
2.5 Points

In 1990, the average duration of long-distance telephone calls originating in one town was 9.3 minutes. A long-distance telephone company wants to perform a hypothesis test to determine whether the average duration of long-distance phone calls has changed from the 1990 mean of 9.3 minutes. Formulate the null and alternative hypotheses for the study described.

 A. Ho: µ = 9.3 minutes     H a : µ < 9.3 minutes B. Ho: µ = 9.3 minutes     H a : µ > 9.3 minutes C. Ho: µ = 9.3 minutes      H a : µ ¹ 9.3 minutes D. Ho: µ ¹ 9.3 minutes     H a : µ = 9.3 minutes
##### Question 11 of 40
2.5 Points

In the past, the mean running time for a certain type of flashlight battery has been 8.0 hours. The manufacturer has introduced a change in the production method and wants to perform a hypothesis test to determine whether the mean running time has increased as a result. The hypotheses are:

H0 : µ  = 8.0 hours

Ha : µ  > 8.0 hours

Explain the meaning of a Type II error.

 A. Concluding that µ > 8.0 hours when in fact µ > 8.0 hours B. Failing to reject the hypothesis that µ = 8.0 hours when in fact µ > 8.0 hours C. Concluding that µ > 8.0 hours D. Failing to reject the hypothesis that µ = 8.0 hours when in fact µ = 8.0 hours
##### Question 12 of 40
2.5 Points
A consumer advocacy group claims that the mean amount of juice in a 16

ounce bottled drink is not 16 ounces, as stated by the bottler.

Determine the null and alternative hypotheses for the test described.

 A. H0: µ = 16 ounces     Ha: µ < 16 ounces B. H0: µ ¹ 16 ounces     Ha: µ = 16 ounces C. H0: µ = 16 ounces     Ha: µ > 16 ounces D. H0: µ = 16 ounces      Ha: µ ¹ 16 ounces
##### Question 13 of 40
2.5 Points
The owner of a football team claims that the average attendance at home games is over 3000, and he is therefore justified in moving the team to a city with a larger stadium. Assuming that a hypothesis test of the claim has been conducted and that the conclusion is failure to reject the null hypothesis, state the conclusion in non-technical terms.

 A. There is sufficient evidence to support the claim that the mean attendance is greater than 3000. B. There is sufficient evidence to support the claim that the mean attendance is equal to 3000. C. There is not sufficient evidence to support the claim that the mean attendance is greater than 3000. D. There is not sufficient evidence to support the claim that the mean attendance is less than 3000.
##### Question 14 of 40
2.5 Points

without computing a P-value, determine whether the alternate hypothesis is supported and give a reason for your conclusion.

 A. is less than 1 standard deviation above the claimed mean. B. is more than 4 standard deviations above the claimed mean. C. is less than 1 standard deviation above the claimed mean. D. is more than 4 standard deviations above the claimed mean.
##### Question 15 of 40
2.5 Points
A two-tailed test is conducted at the 5% significance level. What is the P-value required to reject the null hypothesis?

 A. Greater than or equal to 0.10 B. Less than or equal to 0.05 C. Less than or equal to 0.10 D. Greater than or equal to 0.05
##### Question 16 of 40
2.5 Points

z = 1.8 for Ha:  µ >  claimed value. What is the P-va