Carter motor company claims that its new sedan the libra

1. Use the given degree of confidence and sample data to construct a confidence interval for the population mean μ. Assume that the population has a normal distribution.

A laboratory tested twelve chicken eggs and found that the mean amount of cholesterol was 185 milligrams with s = 17.6 milligrams. A confidence interval of 173.8 mg < μ < 196.2 mg is constructed for the true mean cholesterol content of all such eggs. It was assumed that the population has a normal distribution. What confidence level does this interval represent?

A. 80%

B. 95%

C. 99%

D. 98%

2. Express a confidence interval defined as (0.432, 0.52) in the form of the point estimate ________ ± the margin of error ________. Express both in three decimal places.

A. 0.476; 0.044

B. 0.476; 0.088

C. 0.432; 0.088

D. 0.432; 0.044

3. The following table describes the results of roadworthiness tests of Ford Focus cars that are three years old (based on data from the Department of Transportation). The random variable x represents the number of cars that failed among six that were tested for roadworthiness:

x P(x)

0 0.377

1 0.399

2 0.176

3 0.041

4 0.005

5 0+

6 0+

Find the probability of getting three or more cars that fail among six cars tested.

A. 0.222

B. 0.048

C. 0.046

D. 0.005

4. Formulate the indicated conclusion in nontechnical terms. Be sure to address the original claim. Carter Motor Company claims that its new sedan, the Libra, will average better than 32 miles per gallon in the city. Assuming that a hypothesis test of the claim has been conducted and that the conclusion is to reject the null hypothesis, state the conclusion in nontechnical terms.

A. There is not sufficient evidence to support the claim that the mean is greater than 32 miles per gallon.

B. There is sufficient evidence to support the claim that the mean is less than 32 miles per gallon.

C. There is not sufficient evidence to support the claim that the mean is less than 32 miles per gallon.

D. There is sufficient evidence to support the claim that the mean is greater than 32 miles per gallon.

5. Which of the following is a biased estimator?

A. variance

B. proportion

C. mean

D. standard deviation

6. The following table describes the results of roadworthiness tests of Ford Focus cars that are three years old (based on data from the Department of Transportation). The random variable x represents the number of cars that failed among six that were tested for roadworthiness:

x P(x)

0 0.377

1 0.399

2 0.176

3 0.041

4 0.005

5 0+

6 0+

Is the probability of getting three or more cars that fail among six cars tested significant, determined by a cutoff value of 0.05?

A. Yes

B. No

7. Use the given information to find the P-value. Also, use a 0.05 significance level and state the conclusion about the null hypothesis (reject the null hypothesis or fail to reject the null hypothesis). With H 1 : p ≠ 0.377 the test statistic is z = 3.06.

A. 0.0011; reject the null hypothesis

B. 0.0022; fail to reject the null hypothesis

C. 0.0022; reject the null hypothesis

D. 0.0011; fail to reject the null hypothesis

8. Identify the given random variable as being discrete or continuous. The cost of a randomly selected orange.

A. Continuous

B. Discrete

8. A tennis player makes a successful first serve 51% of the time. If she serves 9 times, what is the probability that she gets exactly 3 successful first serves in? Assume that each serve is independent of the others.

A. 0.154

B. 0.00184

C. 0.133

D. 0.0635

9. Which of the following critical values is appropriate for a 98% confidence level where n = 7; σ = 27 and the population appears to be normally distributed.

A. zα/2 = 2.05

B. tα/2 = 2.575

C. zα/2 = 2.33

D. tα/2 = 1.96

10. A die is rolled nine times and the number of times that two shows on the upper face is counted. If this experiment is repeated many times, find the mean for the number of twos.

A. 2.25 twos

B. 1.5 twos

C. 3 twos

D. 7.5 twos

11. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

n = 56, x = 30; 95% confidence

A. 0.425 < p < 0.647

B. 0.426 < p < 0.646

C. 0.404 < p < 0.668

D. 0.405 < p < 0.667

12. Find the P-value for the indicated hypothesis test. An article in a journal reports that 34% of American fathers take no responsibility for child care. A researcher claims that the figure is higher for fathers in the town of Littleton. A random sample of 225 fathers from Littleton, yielded 97 who did not help with child care. Find the P-value for a test of the researcher's claim.

A. 0.0529

B. 0.0015

C. 0.0038

D. 0.0019

13. Express the null hypothesis and the alternative hypothesis in symbolic form. Use the correct symbol ( μ, p, σ) for the indicated parameter. The manufacturer of a refrigerator system for beer kegs produces refrigerators that are supposed to maintain a true mean temperature, μ, of 48° F, ideal for a certain type of German pilsner. The owner of the brewery does not agree with the refrigerator manufacturer, and claims he can prove that the true mean temperature is incorrect.

A. H0 : μ ≥ 48° H1 : μ < 48°

B. H0 : μ ≠ 48° H1 : μ = 48°

C. H0 : μ ≤ 48° H1 : μ > 48°

D. H0 : μ = 48° H1 : μ ≠ 48°

14. The Acme Candy Company claims that 60% of the jawbreakers it produces weigh more than 0.4 ounces. Suppose that 800 jawbreakers are selected at random from the production lines. Would it be significant for this sample of 800 to contain 494 jawbreakers that weigh more than 0.4 ounces? Consider as significant any result that differs from the mean by more than 2 standard deviations. That is, significant values are either less than μ - 2 σ or greater than μ + 2 σ.

A. Yes

B. No

15. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

n = 130, x = 69; 90% confidence

A. 0.463 < p < 0.599

B. 0.459 < p < 0.603

C. 0.461 < p < 0.601

D. 0.458 < p < 0.604

16. Scores on a test are normally distributed with a mean of 63.2 and a standard deviation of 11.7. Find P 81, which separates the bottom 81% from the top 19%.

A. 0.291

B. 66.6

C. 73.5

D. 0.88

17. In one region, the September energy consumption levels for single -family homes are found to be normally distributed with a mean of 1050 kWh and a standard deviation of 218 kWh. For a randomly selected home, find the probability that the September energy consumption level is between 1100 kWh and 1225 kWh.

A. 0.3791

B. 0.1971

C. 0.0910

D. 0.2881

18. A bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard deviation of 50. If an applicant is randomly selected, find the probability of a rating that is between 200 and 275.

A. 0.0668

B. 0.4332

C. 0.9332

D. 0.5

19. Determine whether the given procedure results in a binomial distribution. If not, state the reason why. Rolling a single die 26 times, keeping track of the numbers that are rolled.

A. Not binomial: the trials are not independent.

B. The procedure results in a binomial distribution.

C. Not binomial: there are more than two outcomes for each trial.

D. Not binomial: there are too many trials.

20. Determine whether the given procedure results in a binomial distribution. If not, state the reason why. Rolling a single die 53 times, keeping track of the "fives" rolled.

A. The procedure results in a binomial distribution.

B. Not binomial: the trials are not independent.

C. Not binomial: there are more than two outcomes for each trial.

D. Not binomial: there are too many trials.