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Statistics practice quiz

I had another web site do this class and they got a 50 percent on the pretest. Please do better.
Question 1 (5 points)
A toy manufacturer produces battery-operated games. A random sample of 25 games averaged 15 operating hours on a set of batteries, with a standard deviation of 1.6 hours. Calculate the interval estimate with 95 percent confidence for the average operating time on a set of batteries for all of the manufacturer's games.

a. 14.11 - 15.9 hours
b. 14.18 - 15.82 hours
c. 14.34 - 15.66 hours
d. 14.37 - 15.63 hours

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Question 2 (10 points)

The Oklahoma Department of Public Safety believes that the average speed of automobiles traveling on I-35 is 65 mph. A random sample of 25 automobiles is taken between Norman and Moore. The sample has a mean speed of 72 mph and a standard deviation of 10 mph.

Test the department's belief that the average speed in I-35 is 65 mph.

a. Accept department's belief
b. Reject department's belief
c. Not enough information to make a judgment
d. Needs to undergo further testing

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Question 3 (10 points)
A national sports magazine reports that the people who watch Monday night football are evenly divided between men and women. You want to test the magazine's claim at a 95 percent level of confidence. What is the minimum number of respondents needed to ensure that you are within one percent (1%) of the actual proportion?

a. 49
b. 98
c. 2401
d. 9604

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Question 4 (10 points)
You conduct a random sample of those who regularly watch Monday night football. Of the 12,000 people sampled 6,600 are men. Test the sport magazine's hypothesis that the proportion of men and women who watch Monday night football is evenly divided. Based on the results of your test the p-value is

a. 0.0000
b. 0.0911
c. 0.5000
d. 1.0000

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Question 5 (10 points)
A national sports magazine reports that the people who watch Monday night football are evenly divided between men and women. You conduct a random sample of those who regularly watch Monday night football. From a sample of 10,000 participants, 5,283 are men. Test the sport magazine's hypothesis that the proportion of men and women who watch Monday night football is evenly divided. As a result of your test, the null hypothesis should

a. be rejected.
b. not be rejected
c. altered to not exploit gender differences.
d. reconsidered because the outcome was inconclusive.

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Question 6 (5 points)
The turnpike authority is concerned with the number of vehicles waiting in line at the toll booths. During a two-hour period, 120 of the 250 people that passed through a toll booth did not have the correct change. Calculate an interval estimate with 95 percent confidence for the actual proportion of all people who pass through the toll booths without the correct change.

a. LCL = .418, UCL = .542
b. LCL = .428, UCL = .532
c. not enough information to calculate an estimate
d. will vary between weekdays and weekends

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Question 7 (5 points)

Bags of a certain brand of tortilla chips claim to have a net weight of 14 ounces. Net weights actually vary from bag to bag and are normally distributed. A representative of a consumer advocate group wishes to determine the mean weight for all bags tortilla chips. To do this, the representative randomly selects 16 bags of chips and weighs each bag. The sample mean is 13.8 ounces with a standard deviation of 0.24 ounces.

Construct a 95 percent conficence interval for the mean weight for all bags of tortilla chips.

a. 13.872 - 14.128 ounces
b. 13.823 - 14.177 ounces
c. 13.672 - 13.928 ounces
d. 13.643 - 13.997 ounces

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Question 8 (10 points)

An economist for the International Monetary Fund (IMF) recently stated that debtor nations have higher inflation rates that creditor nations. A survey of 15 creditor nations in the world revealed an average inflation rate of 5.23 percent with a standard deviation of 1.23 percent. Twenty debtor nations revealed an average inflation rate of 7.88 percent with a standard deviation of 2.22 percent. Test the economist's premise to determine if there is a significant difference in the inflation rate of creditor versus debtor nations.

The p-value for your test is

a. 0.0000
b. 0.0495
c. 0.0990
d. 1.0000

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Question 9 (15 points)

While cable television companies in Minnesota are prohibited from holding exclusive rights to an area, the laws do not demand that a company face competition (Gross, 1993). Many subscribers feel that these de facto monopolies exploit consumers by charging excessive monthly cable fees. A congressional subcomittee is considering regulation of the cable industry. The subcomittee randomly sample basic cable rates for six companies that have no competition, and six companies with competitors. The observed rates are contained in the table below.

No Competition: $18.44 $26.88 $22.87 $25.78 $23.34 $27.52
Competition: $18.95 $23.74 $17.25 $20.14 $18.98 $20.14

Test to determine if there is a significant difference between the average basic cable rates of the two groups. (Hint: create two lists and input data.)

Based on the test, the congressional subcommittee should

a. reject the null hypothesis because there is a definite difference between the two average basic cable rates.
b. reject the subscribers claim because there is no significant difference between the two average basic cable rates.
c. pass the decision to the Federal Communications Commission (FCC) who would have direct regulatory control over the cable industry.
d. table the issue until after the next general election.

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Question 10 (5 points)
Recently, an automobile insurance company randomly selected samples of 300 single male and 300 married male policyholders all between the ages of 25 and 30 years. During the past three years, 57 of the single and 36 of the married policyholders reported accidents. Calculate an interval estimate with 99 percent confidence for the difference in accident rates between all single and married male policyholders, ages 25 to 30 years.

a. LCL = -0.017, UCL = 0.157
b. LCL = 0.0, UCL = 0.146
c. LCL = 0.022, UCL = 0.118
d. cannot be determined

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Question 11 (15 points)
Antigun proponents are voicing alarm over the increasing number of homes with children and handguns after the concealed-carry passed. A survey taken before the law was effective indicated that handguns were in 28 of 150 households with children. An after-law survey revealed that handguns were in 52 of 200 households with children. Test to determine if there is a significant difference in households with children that have handguns before and after the concealed-carry law. Based on your test, we should

a. not reject the antigun proponents premise
b. accept the antigun proponents premise and order a recount.
c. reject the antigun proponents premise
d. accept the antigun proponents premise because you have stock in a copmany that produces trigger locks.

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Solution Preview

Please see the attached Word document. For each of the multiple choice questions, I have underlined the correct choice. This is a statistics practice quiz for a first semester statistics class. There are 11 problems on the quiz covering the ...

Solution Summary

This is a statistics practice quiz for a first semester statistics class. There are 11 problems on the quiz covering the following topics:

1. Confidence interval for a population mean
2. Hypothesis test for a population mean
3. Sample size for a population proportion (binomial proportion)
4. Hypothesis test for a population proportion
5. Confidence interval for a population proportion
6. Confidence interval for the difference between two population means
7. Hypothesis test for the difference between two population means
8. Confidence interval for the difference between two population proportions
9. Hypothesis test for the difference between two population proportions

I have provided the correct choice for each of the questions as well as details showing how the calculations for each question should be done.

$2.19