Q&A Hero

Q: When using Excel to calculate a p"value for a lower-tail hypothesis test, the following must be useda. RANDb. 1 -NORMSDISTc. NORMSDISTd. Not enough information is given to answer this question.

Q: When using Excel to calculate a p"value for an upper-tail hypothesis test, the following must be useda. RANDb. 1 -NORMSDISTc. NORMSDISTd. Not enough information is given to answer this question.

Q: Excel's __________ function can be used to calculate a p-value for a hypothesis test. a. RAND b. NORMSDIST c. NORMSINV d. Not enough information is given to answer this question.

Q: A two-tailed test is performed at a 5% level of significance. The p-value is determined to be 0.09. The null hypothesis a. must be rejected b. should not be rejected c. may or may not be rejected, depending on the sample size. d. has been designed incorrectly

Q: Refer to Exhibit 9-3. If the test is done at a 5% level of significance, the null hypothesis should a. not be rejected b. be rejected c. Not enough information given to answer this question. d. None of the other answers are correct.

Q: Refer to Exhibit 9-3. The p-value is equal to a. 0.1151 b. 0.3849 c. 0.2698 d. 0.2302

Q: Exhibit 9-3n = 49H0: = 50= 54.8Ha: 50 = 28Refer to Exhibit 9-3. The test statistic equalsa. 0.1714b. 0.3849c. -1.2d. 1.2

Q: Refer to Exhibit 9-2. At a .05 level of significance, it can be concluded that the mean of the population isa. significantly greater than 3b. not significantly greater than 3c. significantly less than 3d. significantly greater then 3.18

Q: Refer to Exhibit 9-2. The p-value is a. 0.025 b. 0.0456 c. 0.05 d. 0.0228

Q: Exhibit 9-2The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minutes. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes.Refer to Exhibit 9-2. The test statistic isa. 1.96b. 1.64c. 2.00d. 0.056

Q: Refer to Exhibit 9-1. If the test is done at a .05 level of significance, the null hypothesis shoulda. not be rejectedb. be rejectedc. Not enough information is given to answer this question.d. None of the other answers are correct.

Q: Refer to Exhibit 9-1. The p-value is a. 0.5107 b. 0.0214 c. 0.0107 d. 2.1

Q: Exhibit 9-1n = 36H0: 20= 24.6Ha: > 20 = 12Refer to Exhibit 9-1. The test statistic equalsa. 2.3b. 0.38c. -2.3d. -0.38

Q: When the p-value is used for hypothesis testing, the null hypothesis is rejected ifa. p-value <b. < p-valuec. p-value > d. p-value = z

Q: Which of the following does notneed to be known in order to compute the p-value?a. knowledge of whether the test is one-tailed or two-tailedb. the value of the test statisticc. the level of significanced. All of these are needed.

Q: A p-value is thea. probability, when the null hypothesis is true, of obtaining a sample result that is at least as unlikely as what is observedb. value of the test statisticc. probability of a Type II errord. probability corresponding to the critical value(s) in a hypothesis test

Q: If a hypothesis is not rejected at a 5% level of significance, it will a. also not be rejected at the 1% level b. always be rejected at the 1% level c. sometimes be rejected at the 1% level d. Not enough information is given to answer this question.

Q: If a hypothesis is rejected at a 5% level of significance, it a. will always be rejected at the 1% level b. will always be accepted at the 1% level c. will never be tested at the 1% level d. may be rejected or not rejected at the 1% level

Q: For a two-tailed test with a sample size of 40, the null hypothesis will notbe rejected at a 5% level of significance if the test statistic is a. between -1.96 and 1.96, exclusively b. greater than 1.96 c. less than 1.645 d. greater than -1.645

Q: For a one-tailed test (upper tail) with a sample size of 900, the null hypothesis will be rejected at the .05 level of significance if the test statistic is a. less than or equal to -1.645 b. greater than or equal to 1.645 c. less than 1.645 d. less than -1.96

Q: In order to test the hypotheses H0: 100 and Ha: > 100 at an level of significance,the null hypothesis will be rejected if the test statistic zisa. >zb. < zc. <-zd. < 100

Q: When the hypotheses H0: 100 and Ha: < 100 are being tested at a level of significance of , the null hypothesis will be rejected if the test statistic zisa. b. > -zc. < -zd. < 100

Q: Read the zstatistic from the normal distribution table and circle the correct answer. A one-tailed test (upper tail) at a .123 level of significance; z= a. 1.54 b. 1.96 c. 1.645 d. 1.16

Q: Read the zstatistic from the normal distribution table and circle the correct answer. A one-tailed test (lower tail) at a .063 level of significance; z= a -1.86 b. -1.53 c. -1.96 d. -1.645

Q: Read the zstatistics from the normal distribution table and circle the correct answer. A two-tailed test at a .0694 level of significance; z= a. -1.96 and 1.96 b. -1.48 and 1.48 c. -1.09 and 1.09 d. -0.86 and 0.86

Q: A two-tailed test is a a. hypothesis test in which rejection region is in both tails of the sampling distribution b. hypothesis test in which rejection region is in one tail of the sampling distribution c. hypothesis test in which rejection region is only in the lower tail of the sampling distribution d. hypothesis test in which rejection region is only in the upper tail of the sampling distribution

Q: A one-tailed test is a a. hypothesis test in which rejection region is in both tails of the sampling distribution b. hypothesis test in which rejection region is in one tail of the sampling distribution c. hypothesis test in which rejection region is only in the lower tail of the sampling distribution d. hypothesis test in which rejection region is only in the upper tail of the sampling distribution

Q: In hypothesis testing, the critical value is a. a number that establishes the boundary of the rejection region b. the probability of a Type I error c. the probability of a Type II error d. the same as the p-value

Q: If the level of significance of a hypothesis test is raised from .01 to .05, the probability of a Type II error a. will also increase from .01 to .05 b. will not change c. will decrease d. Not enough information is given to answer this question.

Q: The probability of rejecting a false null hypothesis is equal toa. 1 - b. 1 - c. d.

Q: The probability of making a Type II error is denoted bya. b. c. 1 - d. 1 -

Q: The level of significance can be any a. negative value b. value c. value larger than 0.1 d. None of the answers is correct.

Q: In the hypothesis testing procedure, isa. the level of significanceb. the critical valuec. the confidence leveld. 1 - level of significance

Q: The level of significance in hypothesis testing is the probability of a. accepting a true null hypothesis b. accepting a false null hypothesis c. rejecting a true null hypothesis d. could be any of the above, depending on the situation

Q: The level of significance is the a. maximum allowable probability of Type II error b. maximum allowable probability of Type I error c. same as the confidence coefficient d. same as the p-value

Q: The probability of making a Type I error is denoted bya. b. c. 1 - d. 1 -

Q: A Type II error is committed when a. a true alternative hypothesis is mistakenly rejected b. a true null hypothesis is mistakenly rejected c. the sample size has been too small d. not enough information has been available

Q: In hypothesis testing if the null hypothesis has been rejected when the alternative hypothesis has been true, a. a Type I error has been committed b. a Type II error has been committed c. either a Type I or Type II error has been committed d. the correct decision has been made

Q: The error of rejecting a true null hypothesis is a. a Type I error b. a Type II error c. can be either a or b, depending on the situation d. committed when not enough information is available

Q: If a hypothesis test leads to the rejection of the null hypothesis, a a. Type II error must have been committed b. Type II error may have been committed c. Type I error must have been committed d. Type I error may have been committed

Q: In hypothesis testing if the null hypothesis is rejected, a. no conclusions can be drawn from the test b. the alternative hypothesis must also be rejected c. the data must have been accumulated incorrectly d. None of the other answers are correct.

Q: The manager of an automobile dealership is considering a new bonus plan in order to increase sales. Currently, the mean sales rate per salesperson is five automobiles per month. The correct set of hypotheses for testing the effect of the bonus plan is

Q: A soft drink filling machine, when in perfect adjustment, fills the bottles with 12 ounces of soft drink. Any overfilling or underfilling results in the shutdown and readjustment of the machine. To determine whether or not the machine is properly adjusted, the correct set of hypotheses is

Q: The average life expectancy of tires produced by the Whitney Tire Company has been 40,000 miles. Management believes that due to a new production process, the life expectancy of its tires has increased. In order to test the validity of this belief, the correct set of hypotheses is

Q: A student believes that the average grade on the final examination in statistics is at least 85. She plans on taking a sample to test her belief. The correct set of hypotheses is

Q: A meteorologist stated that the average temperature during July in Chattanooga was 80 degrees. A sample of 32 Julys was taken. The correct set of hypotheses is

Q: Your investment executive claims that the average yearly rate of return on the stocks she recommends is at least 10.0%. You plan on taking a sample to test her claim. The correct set of hypotheses is

Q: In hypothesis testing, the alternative hypothesis is a. the hypothesis tentatively assumed true in the hypothesis-testing procedure b. the hypothesis concluded to be true if the null hypothesis is rejected c. the maximum probability of a Type I error d. All of the answers are correct.

Q: In hypothesis testing, the hypothesis tentatively assumed to be true is a. the alternative hypothesis b. the null hypothesis c. either the null or the alternative d. None of the other answers are correct.

Q: An example of statistical inference is a. a population mean b. descriptive statistics c. calculating the size of a sample d. hypothesis testing

Q: For a two-tailed hypothesis test about , we can use any of the following approaches excepta. compare the confidence interval estimate of to the hypothesized value of b. compare the p-value to the value of c. compare the value of the test statistic to the critical valued. compare the level of significance to the confidence coefficient

Q: Which of the following is an improper form of the null and alternative hypotheses? a. and b. and c. and d. and

Q: In tests about a population proportion, p0represents the a. hypothesized population proportion b. observed sample proportion c. observed p-value d. probability of

Q: When the rejection region is in the lower tail of the sampling distribution, the p-value is the area under the curve a. less than or equal to the critical value b. less than or equal to the test statistic c. greater than or equal to the critical value d. greater than or equal to the test statistic

Q: If the cost of a Type I error is high, a smaller value should be chosen for the a. critical value b. confidence coefficient c. level of significance d. test statistic

Q: The practice of concluding "do not reject H0" is preferred over "accept H0" when we a. are conducting a one-tailed test b. are testing the validity of a claim c. have an insufficient sample size d. have not controlled for the Type II error

Q: Which of the following hypotheses applies to a situation where action must be taken both when H0cannot be rejected and when H0can be rejected? a. b. c. d.

Q: A Type I error is committed when a. a true alternative hypothesis is not accepted b. a true null hypothesis is rejected c. the critical value is greater than the value of the test statistic d. sample data contradict the null hypothesis

Q: As a general guideline, the research hypothesis should be stated as the a. null hypothesis b. alternative hypothesis c. tentative assumption d. hypothesis the researcher wants to disprove

Q: Two approaches to drawing a conclusion in a hypothesis test are a. p-value and critical value b. one-tailed and two-tailed c. Type I and Type II d. null and alternative

Q: More evidence against H0is indicated by a. lower levels of significance b. smaller p-values c. smaller critical values d. lower probabilities of a Type II error

Q: The manager of University Credit Union (UCU) is concerned about checking account transaction discrepancies. Customers are bringing transaction errors to the attention of the bank's staff several months after they occur. The manager would like to know what proportion of his customers balance their checking accounts within 30 days of receiving a transaction statement from the bank.Using random sampling, 400 checking account customers are contacted by telephone and asked if they routinely balance their accounts within 30 days of receiving a statement. 271 of the 400 customers respond Yes.a. Develop a 95% confidence interval estimate for the proportion of the population of checking account customers at UCU that routinely balance their accounts in a timely manner.b. Suppose UCU wants a 95% confidence interval estimate of the population proportion with a margin of error of E= .025. How large a sample size is needed?

Q: The manager of Hudson Auto Repair wants to advertise one price for an engine tune-up, with parts included. Before he decides the price to advertise, he needs a good estimate of the average cost of tune-up parts. A sample of 20 customer invoices for tune-ups has been taken and the costs of parts, rounded to the nearest dollar, are listed below.9178935775529980105621047462689773776580109Provide a 90% confidence interval estimate of the mean cost of parts per tune-up for all of the tune-ups performed at Hudson Auto Repair.

Q: A marketing firm is developing a new television advertisement for a large discount retail chain. A sample of 30 people is shown two potential ads and asked their preference. The results for ad #1 follow. Use Excel to develop a 95% confidence interval estimate of the proportion of people in the population who will prefer ad #1.Prefer Advertisement #1yesnonoyesyesnonononoyesnoyesnonoyesyesyesnoyesyesnononoyesyesnoyesyesnono

Q: Six hundred consumers were asked whether they would like to purchase a domestic or a foreign automobile. Their responses are given below.PreferenceFrequencyDomestic240Foreign360Develop a 95% confidence interval for the proportion of all consumers who prefer to purchase domestic automobiles.

Q: In a random sample of 500 college students, 23% say that they read or watch the news every day. Develop a 90% confidence interval for the population proportion. Interpret your results.

Q: In a random sample of 400 registered voters, 120 indicated they plan to vote for Candidate A. Determine a 95% confidence interval for the proportion of all the registered voters who will vote for Candidate A.

Q: You are given the following information obtained from a random sample of 4 observations taken from a large, normally distributed population.25473256Construct a 95% confidence interval for the mean of the population.

Q: A statistician selected a sample of 16 accounts receivable and determined the mean of the sample to be $5,000 with a standard deviation of $400. She reported that the sample information indicated the mean of the population ranges from $4,739.80 to $5,260.20. She did not report what confidence coefficient she had used. Based on the above information, determine the confidence coefficient that was used.

Q: The proprietor of a boutique in New York wanted to determine the average age of his customers. A random sample of 25 customers revealed an average age of 28 years with a standard deviation of 10 years. Determine a 95% confidence interval estimate for the average age of all his customers. Assume the population of customer ages is normally distributed.

Q: A sample of 16 students from a large university is taken. The average age in the sample was 22 years with a standard deviation of 6 years. Construct a 95% confidence interval for the average age of the population. Assume the population of student ages is normally distributed.

Q: A sample of 25 patients in a doctor's office showed that they had to wait an average of 35 minutes with a standard deviation of 10 minutes before they could see the doctor. Provide a 98% confidence interval estimate for the average waiting time of all the patients who visit this doctor. Assume the population of waiting times is normally distributed.

Q: A simple random sample of 25 items from a normally distributed population resulted in a sample mean of 28 and a standard deviation of 7.5. Construct a 95% confidence interval for the population mean.

Q: Computer Services, Inc. wants to determine a confidence interval for the average CPU time of their teleprocessing transactions. A sample of 196 transactions yielded a mean of 5 seconds. The population standard deviation is 1.4 seconds. Determine a 97% confidence interval for the average CPU time.

Q: The Highway Safety Department wants to study the driving habits of individuals. A sample of 41 cars traveling on the highway revealed an average speed of 60 miles per hour and a standard deviation of 7 miles per hour. The population of car speeds is approximately normally distributed. Determine a 90% confidence interval estimate for the speed of all cars.

Q: A random sample of 81 children with working mothers showed that they were absent from school an average of 6 days per term. The population standard deviation is known to be 1.8 days. Provide a 90% confidence interval for the average number of days absent per term for all the children.

Q: A random sample of 26 checking accounts at a bank showed an average daily balance of $300 and a standard deviation of $45. The balances of all checking accounts at the bank are normally distributed. Develop a 95% confidence interval estimate for the mean of the population.

Q: A newspaper wants to estimate the proportion of Americans who will vote for Candidate A. A random sample of 1000 voters is taken. Of the 1000 respondents, 526 say that they will vote for Candidate A. Which Excel function would be used to construct a confidence interval estimate?a. NORMSINVb. NORMINVc. TINVd. INT

Q: A manufacturer wants to estimate the proportion of defective items that are produced by a certain machine. A random sample of 50 items is taken. Which Excel function would notbe appropriate to construct a confidence interval estimate? a. NORMSINV b. COUNTIF c. STDEV d. All are appropriate.

Q: For which of the following values of pis the value of p(1 - p) maximized? a. p= 0.99 b. p= 0.90 c. p= 1.0 d. p= 0.50