I need someone that is really good in business statistics. 4 test at 10.00 each

Student ID: 22357317

Exam: 250713RR - Sampling Distributions and Estimation; Hypothesis Testing

When you have completed your exam and reviewed your answers, click Submit Exam. Answers will not be recorded until you hit Submit Exam. If you need to exit before completing the exam, click Cancel Exam.

Questions 1 to 20: Select the best answer to each question. Note that a question and its answers may be split across a page break, so be sure that you have seen the entire question and all the answers before choosing an answer.

1. What sample size is required from a very large population to estimate a population proportion within 0.05 with 95% confidence? Don't assume any particular value for p. A. 385

B. 38

C. 271

D. 767

2. In a simple random sample from a population of several hundred that's approximately normally distributed, the following data values were collected.

68, 79, 70, 98, 74, 79, 50, 102, 92, 96

Based on this information, the confidence level would be 90% that the population mean is somewhere between A. 69.15 and 92.45.

B. 71.36 and 90.24.

C. 65.33 and 95.33.

D. 73.36 and 88.24.

3. For 1996, the U.S. Department of Agriculture estimated that American consumers would have eaten, on average, 2.6 pounds of cottage cheese throughout the course of that year. Based on a longitudinal study of 98 randomly selected people conducted during 1996, the National Center for Cottage Cheese Studies found an average cottage cheese consumption of 2.75 pounds and a standard deviation of s = 14 ounces. Given this information, which of the following statements would be correct concerning a two-tail test at the 0.05 level of significance? A. We can conclude that we can't reject the claim that the average cottage cheese consumption in America is 2.6 pounds per person per year.

B. We can conclude that the average cottage cheese consumption in America is at least 0.705 pound more or less than 2.75 pounds per person per year.

C. We can conclude that the average cottage cheese consumption in America is actually 2.75 pounds per person per year.

D. We can conclude that the average cottage cheese consumption in America isn't 2.6 pounds per person per year.

4. Which of the following statements about p-value testing is true? A. The p represents sample proportion.

B. P-value testing applies only to one-tail tests.

C. The p-value is the lowest significance level at which you should reject H 0 .

D. P-value testing uses a predetermined level of significance.

5. Consider a null hypothesis stating that the population mean is equal to 52, with the research hypothesis that the population mean is not equal to 52. Assume we have collected 38 sample data from which we computed a sample mean of 53.67 and a sample standard deviation of 3.84. Further assume the sample data appear approximately normal. What is the test statistic? A. –2.68

B. 2.64

C. 2.68

D. –2.64

6. The commissioner of the state police is reported as saying that about 10% of reported auto thefts involve owners whose cars haven't really been stolen. What null and alternative hypotheses would be appropriate in evaluating this statement made by the commissioner? A. H0: p ≤ 0.10 and H1: p > 0.10

B. H 0

: p = 0.10 and H 1

: p ≠ 0.10

C. H0: p ≥ 0.10 and H1: p < 0.10

D. H 0

: p > 0.10 and H 1

: p ≤ 0.10

7. If the level of significance (α) is 0.005 in a two-tail test, how large is the nonrejection region under the curve of the t distribution? A. 0.005

B. 0.995

C. 0.9975

D. 0.050

8. To schedule appointments better, the office manager for an ophthalmologist wants to estimate the average time that the doctor spends with each patient. A random sample of 49 is taken, and the sample mean is 20.3 minutes. Assume that the office manager knows from past experience that the standard deviation is 14 minutes. She finds that a 95% confidence interval is between 18.3 and 22.3 minutes. What is the point estimate of the population mean, and what is the confidence coefficient? A. 18.3, 0.95

B. 20.3, 95%

C. 20.3, 0.95

D. 18.3, 95%

9. A human resources manager wants to determine a confidence interval estimate for the mean test score for the next office-skills test to be given to a group of job applicants. In the past, the test scores have been normally distributed with a mean of 74.2 and a standard deviation of 30.9. Determine a 95% confidence interval estimate if there are 30 applicants in the group. A. 68.72 to 79.68

B. 63.14 to 85.26

C. 64.92 to 83.48

D. 13.64 to 134.76

10. What is the primary reason for applying a finite population correction coefficient? A. If you don't apply the correction coefficient, your confidence intervals will be too narrow, and thus overconfident.

B. If you don't apply the correction coefficient, you won't have values to plug in for all the variables in the confidence interval formula.

C. When the sample is a very small portion of the population, the correction coefficient is required.

D. If you don't apply the correction coefficient, your confidence intervals will be too broad, and thus less useful in decision making.

11. Which of the following statements correctly compares the t-statistic to the z-score when creating a confidence interval? A. The value of z relates to a normal distribution, while the value of t relates to a Poisson distribution.

B. Using t is easier because you do not have to worry about the degrees of freedom, as you do with z.

C. You can use t all the time, but for n ≥ 30 there is no need, because the results are almost identical if you use t or z. D. Use t when the sample size is small, and the resulting confidence interval will be narrower.

12. A federal auditor for nationally chartered banks, from a random sample of 100 accounts, found that the average demand deposit balance at the First National Bank of Arkansas was $549.82. If the auditor needed a point estimate for the population mean for all accounts at this bank, what should he use? A. The average of $549.82 for this sample

B. There's no acceptable value available.

C. The average of $54.98 for this sample

D. The auditor should survey the total of all accounts and determine the mean.

13. A woman and her son are debating about the average length of a preacher's sermons on Sunday morning. Despite the mother's arguments, the son thinks that the sermons are more than twenty minutes. For one year, he has randomly selected 12 Sundays and found an average time of 26.42 minutes with a standard deviation of 6.69 minutes. Assuming that the population is normally distributed and using a 0.05 level of significance, he wishes to determine whether he is correct in thinking that the average length of sermons is more than 20 minutes. What is the test statistic? A. 6.69

B. –3.32

C. 0.95

D. 3.32

14. Because of the popularity of movies as an entertainment medium for adolescents, an entrepreneur plans to do a national study of the average cost of a movie ticket. If you assume that s = $0.50, what sample size would the entrepreneur have to take to be 95% confident that the estimate was within $0.25 of the true mean ticket prices? A. 4

B. 8

C. 16

D. 15

15. The power of a test is the probability of making a/an _______ decision when the null hypothesis is _______. A. correct, false

B. incorrect, false

C. incorrect, true

D. correct, true

16. Consider a null hypothesis stating that the population mean is equal to 52, with the research hypothesis that the population mean is not equal to 52. Assume we have collected 38 sample data from which we computed a sample mean of 53.67 and a sample standard deviation of 3.84. Further assume the sample data appear approximately normal. What is the p-value you would report for this test? A. 0.0037

B. 0.4963

C. 0.0074

D. 0.0041

17. H0 is p = 0.45 and H1 is p ≠ 0.45. What type of test will be performed?

A. One-tail testing of a proportion

B. One-tail testing of a mean

C. Two-tail testing of a mean

D. Two-tail testing of a proportion

18. A random sample of 10 employees is selected from a large firm. For the 10 employees, the number of days each was absent during the past month was found to be 0, 2, 4, 2, 5, 1, 7, 3, 2, and 4. Of the following values, which would you use as the point estimate for the average number of days absent for all the firm's employees? A. 3

B. 30

C. 4

D. 2.5

19. In the statement of a null hypothesis, you would likely find which of the following terms? A. ≠ B. <

C. =

D. >

20. In sampling without replacement from a population of 900, it's found that the standard error of the

mean, , is only two-thirds as large as it would have been if the population were infinite in size. What is the approximate sample size? A. 600

B. 400

C. 200

End of exam

D. 500