Question: Refer to Exercise 17.16. Are the

> Refer to Exercise 17.14. a. Predict with 95% confidence the MBA program GPA of a BEng whose undergraduate GPA was 9.0, whose GMAT score as 700, and who has had 10 years of work experience. b. Repeat part (a) for a BA student. Data from Exercise 17.14: T

> Refer to Exercise 17.14. After considering the results of the initial study, the dean realized that she may have omitted an important variable— the type of undergraduate degree. She returned to her sample of students and recorded the type of undergraduat

> In a study of computer applications, a survey asked which microcomputer a number of companies used. The following indicator variables were created. Which computer is being referred to by each of the following pairs of values? a. I1 = 0; I2 = 1 b. I1 = 1

> Create and identify indicator variables to represent the following nominal variables. a. Religious affiliation (Catholic, Protestant, and others) b. Working shift (8 a.m. to 4 p.m., 4 p.m. to 12 midnight, and 12 midnight to 8 a.m.) c. Supervisor (Jack Jo

> How many indicator variables must be created to represent a nominal independent variable that has five categories?

> The production manager of a chemical plant wants to determine the roles that temperature and pressure play in the yield of a particular chemical produced at the plant. From past experience, she believes that when pressure is held constant, lower and high

> Graph y versus x1 for x2 = 1, 2, and 3 for each of the following equations. a. y = 1 + 2x1 + 4x2 b. y = 1 + 2x1 + 4x2 − x1x2

> the value of television commercials is by telephone surveys conducted shortly after commercials are aired. Respondents who watched a certain television station at a given time period, during which the commercial appeared, are asked whether they can recal

> The administrator of a school board in a large county was analyzing the average mathematics test scores in the schools under her control. She noticed that there were dramatic differences in scores among the schools. In an attempt to improve the scores of

> For many cities around the world, garbage is an increasing problem. Many North American cities have virtually run out of space to dump the garbage. A consultant for a large American city decided to gather data about the problem. She took a random sample

> The marketing manager for a chain of hardware stores needed more information about the effectiveness of the three types of advertising that the chain used. These are localized direct mailing (in which flyers describing sales and featured products are dis

> The admissions officer of a university is trying to develop a formal system to decide which students to admit to the university. She believes that determinants of success include the standard variables—high school grades and SAT scores. However, she also

> The manager of a tire store in Minneapolis has been concerned with the high cost of inventory. The current policy is to stock all the snow tires that are predicted to sell over the entire winter at the beginning of the season (end of October). The manage

> Refer to Exercise 16.131. Determine whether there is evidence of first-order autocorrelation. Data from Exercise 16.131: The manager of Colonial Furniture has been reviewing weekly advertising expenditures. During the past 6 months, all advertisements f

> Refer to Exercise 17.3. Is there evidence of positive first-order autocorrelation? Data from Exercise 17.3: The president of a company that manufactures drywall wants to analyze the variables that affect demand for his product. Drywall is used to constr

> Weekly sales of a company’s product (y) and those of its main competitor (x) were recorded for one year. a. Conduct a regression analysis of these data. b. Plot the residuals versus the time periods. Does there appear to be autocorrelation? c. Perform th

> Observations of variables y, x1, and x2 were taken over 100 consecutive time periods. a. Conduct a regression analysis of these data. b. Plot the residuals versus the time periods. Describe the graph. c. Perform the Durbin-Watson test. Is there evidence

> Test the following hypotheses with  = .05. H0: There is no first-order autocorrelation. H1: There is negative first-order autocorrelation. n = 33, k = 4, d = 2.25

> The widespread use of salt on roads in Canada and the northern United States during the winter and acid precipitation throughout the year combine to cause rust on cars. Car manufacturers and other companies offer rustproofing services to help purchasers

> After a recent study, researchers reported on the effects of folic acid on the occurrence of spina bifida—a birth defect in which there is incomplete formation of the spine. A sample of 2,000 women who gave birth to children with spina bifida and who wer

> Test the following hypotheses with = .02. H0: There is no first-order autocorrelation. H1: There is first-order autocorrelation. n = 90, k = 5, d = 1.60

> Test the following hypotheses with  = .05. H0: There is no first-order autocorrelation. H1: There is positive first-order autocorrelation. n = 50, k = 2, d = 1.38

> When one company buys another company, it is not unusual that some workers are terminated. The severance benefits offered to the laid-off workers are often the subject of dispute. Suppose that the Laurier Company recently bought the Western Company and s

> Given the following information, perform the Durbin-Watson test to determine whether first order autocorrelation exists: n = 25, k = 5,= .10, d = .90

> Exercise 13.19 described a survey that asked people between 18 and 34 years of age and 35 to 50 years of age how much time they spent listening to FM radio each day. Also recorded were the amounts spent on music throughout the year. Can we infer that a l

> In addition to the data recorded for Exercises 12.31 and 13.227, we recorded the grade point average of the students who held down parttime jobs. Determine whether there is evidence of a linear relationship between the hours spent at parttime jobs and th

> A computer dating service typically asks for various pieces of information such as height, weight, income, and so on. One such service requested the length of index fingers. The only plausible reason for this request is to act as a proxy on height. Women

> (Exercise 3.67 revisited) A very large contribution to profits for a movie theater is the sale of popcorn, soft drinks, and candy. A movie theater manager speculated that the longer the time between showings of a movie, the greater the sales of concessio

> Mutual funds minimize risks by diversifying the investments they make. There are mutual funds that specialize in particular types of investments. For example, the TD Precious Metal Mutual Fund buys shares in gold mining companies. The value of this mutua

> The analysis that the human resources manager performed in Exercise 16.18 indicated that the dexterity test is not a predictor of job performance. However, before discontinuing the test, he decided that the problem is that the statistical analysis was fl

> Automobile insurance appraisers examine cars that have been involved in accidental collisions and estimate the cost of repairs. An insurance executive claims that there are significant differences in the estimates from different appraisers. To support hi

> Some critics of television complain that the amount of violence shown on television contributes to violence in our society. Others point out that television also contributes to the high level of obesity among children. We may have to add financial proble

> Every year, the U.S. Federal Trade Commission rates cigarette brands according to their levels of tar and nicotine, substances that are hazardous to smokers’ health. Additionally, the commission includes the amount of carbon monoxide, which is a by-produ

> An agronomist wanted to investigate the factors that determine crop yield. Accordingly, she undertook an experiment wherein a farm was divided into 30 one-acre plots. The amount of fertilizer applied to each plot was varied. Corn was then planted, and th

> The president of a company that manufactures car seats has been concerned about the number and cost of machine breakdowns. The problem is that the machines are old and becoming quite unreliable. However, the cost of replacing them is quite high, and the

> The manager of Colonial Furniture has been reviewing weekly advertising expenditures. During the past 6 months, all advertisements for the store have appeared in the local newspaper. The number of ads per week has varied from one to seven. The store’s sa

> Perform a complete diagnostic analysis for Exercise 16.18 to determine whether the required conditions are satisfied.

> Are the required conditions satisfied for Exercise 16.17?

> Check to ensure that the required conditions for Exercise 16.16 are satisfied.

> Are the required conditions satisfied for Exercise 16.15?

> Refer to Exercise 16.14. a. Determine the residuals and the standardized residuals. b. Draw the histogram of the residuals. Does it appear that the errors are normally distributed? Explain. c. Identify possible outliers. d. Plot the residuals versus the

> Most automobile repair shops now charge according to a schedule that is claimed to be based on average times. This means that instead of determining the actual time to make a repair and multiplying this value by their hourly rate, repair shops determine

> Refer to Exercise 16.13. Are the required conditions satisfied? Data from Exercise 16.13: Millions of boats are registered in the United States. As is the case with automobiles, there is an active used-boat market. Many of the boats purchased require ba

> Check the required conditions for Exercise 16.12.

> Refer to Exercise 16.11. a. Determine the residuals and the standardized residuals. b. Draw the histogram of the residuals. Does it appear that the errors are normally distributed? Explain. c. Identify possible outliers. d. Plot the residuals versus the

> Refer to Exercise 16.10. Are the required conditions satisfied? Data from Exercise 16.10: Besides their known long-term effects, do cigarettes also cause short-term illnesses such as colds? To help answer this question, a sample of smokers was drawn. Ea

> Determine whether negative first-order autocorrelation exists when d = 2.85, n = 50, and k = 5. (Use a 1% significance level.)

> Are the required conditions satisfied in Exercise 16.8?

> Perform the Durbin-Watson test at the 5% significance level to determine whether positive first-order autocorrelation exists when d = 1.10, n = 25, and k = 3.

> Calculate and plot the residuals and predicted values of y for Exercise 16.5.

> Refer to Exercise 16.4. a. Calculate the residuals. b. Calculate the predicted values of y. c. Plot the residuals (on the vertical axis) and the predicted values of y. Data from Exercise 16.4: Critics of television often refer to the detrimental effects

> Discrimination in hiring has been illegal for many years. It is illegal to discriminate against any person on the basis of race, gender, or religion. It is also illegal to discriminate because of a person’s handicap if it in no way prevents that person f

> Calculate the residuals and predicted values of y in Exercise 16.3.

> Refer to Exercise 16.2. Calculate the residuals and the predicted values of y. Data from Exercise 16.2: Attempting to analyze the relationship between advertising and sales, the owner of a furniture store recorded the monthly advertising budget ($ thous

> You are given the following six points: a. Determine the regression equation. b. Use the regression equation to determine the predicted values of y. c. Use the predicted and actual values of y to calculate the residuals. d. Compute the standardized resi

> Refer to Exercise 17.15. Determine whether the required conditions are satisfied. Data from Exercise 17.15: With voter turnout during presidential elections around 50%, a vital task for politicians is to try to predict who will actually vote. A variable

> Refer to Exercise 17.15. Check the required conditions. Data from Exercise 17.15: With voter turnout during presidential elections around 50%, a vital task for politicians is to try to predict who will actually vote. A variable used to determine who is

> The general manager of the Cleveland Indians baseball team is in the process of determining which minor-league players to draft. He is aware that his team needs home-run hitters and would like to find a way to predict the number of home runs a player wil

> Refer to Exercise 17.14. Are the required conditions satisfied? Data from Exercise 17.14: The MBA program at a large university is facing a pleasant problem—too many applicants. The current admissions policy requires students to have completed at least

> Refer to Exercise 17.13. a. Are the required conditions satisfied? b. Is multicollinearity a problem? If so, explain the consequences. Data from Exercise 17.13: Lotteries have become important sources of revenue for governments. Many people have critici

> Determine whether there are violations of the required conditions in the regression model used in Exercise 17.11.

> Refer to Exercise 17.10. Calculate the residuals and predicted values. a. Is the normality requirement satisfied? b. Is the variance of the error variable constant? c. Is multicollinearity a problem? Data from Exercise 17.10: Life insurance companies ar

> Health-care costs in the United States and Canada are concerns for citizens and politicians. The question is, How can we devise a system wherein people’s medical bills are covered but individuals attempt to reduce costs? An American company has come up w

> Determine whether the required conditions are satisfied in Exercise 17.9

> Are the required conditions satisfied for the regression analysis in Exercise 17.8?

> Refer to Exercise 17.7. a. Conduct an analysis of the residuals to determine whether any of the required conditions are violated. b. Does it appear that multicollinearity is a problem? c. Identify any observations that should be checked for accuracy. Da

> Are the required conditions satisfied in Exercise 17.6?

> Calculate the residuals and predicted values for the regression analysis in Exercise 17.5. a. Does the error variable appear to be normally distributed? b. Is the variance of the error variable constant? c. Is multicollinearity a problem?

> Pick any one of the previous five exercises and briefly describe why the intervals are so wide.

> Refer to Exercise 16.49. The temperature is 80 degrees. Predict with 95% confidence how far the golfer’s next drive will travel. Data from Exercise 16.49: Refer to Exercise 3.71 wherein we looked at the relationship between temperature and distance that

> Refer to Exercise 16.48. Predict with 90% confidence how definite is the intention to vote for one 50-year-old. Data from Exercise 16.48: In most presidential elections in the United States, the voter turnout is quite low, often in the neighborhood of 5

> Refer to Exercise 16.47. Estimate with 90% confidence the mean number of days watching the national news on television for the population of 70-year-olds. Data from Exercise 16.47: National news on television features commercials describing pharmaceutic

> Refer to Exercise 16.46. Use a prediction interval with 90% confidence to predict the auction selling price of one Canada 1925 nickel with a grade of 40. Data from Exercise 16.46: Refer to Exercise 3.70 where we looked at the relationship between the gr

> A study was undertaken to determine whether a drug commonly used to treat epilepsy could help alcoholics to overcome their addiction. The researchers took a sample of 103 hardcore alcoholics. Fifty-five drinkers were given topiramate and the remaining

> Refer to Exercise 16.45. Estimate with 95% confidence the mean time spent watching or reading news on the Internet for the population of people who have completed 12 years of education. Data from Exercise 16.45: Do more educated people spend more time w

> Refer to Exercise 16.18. Estimate with 95% confidence the mean percentage of defectives for workers who score 80 on the dexterity test. Data from Exercise 16.18: Although a large number of tasks in the computer industry are robotic, many operations requ

> Refer to Exercise 16.17. a. Estimate with 95% confidence the mean annual income of 6’2” (74 inches)-tall men. b. Suppose that an individual is 5’8” (68 inches). Predict with 95% confidence his annual income. Data from Exercise 16.17: One general belief

> Refer to Exercise 16.16. Predict with 95% confidence the monthly office rent in a city when the vacancy rate is 8%. Data from Exercise 16.16: An economist wanted to investigate the relationship between office rents (the dependent variable) and vacancy r

> Refer to Exercise 16.15. Predict the food budget of a family whose household income is $60,000. Use a 90% confidence level. Data from Exercise 16.15: An economist for the federal government is attempting to produce a better measure of poverty than is cu

> Refer to Exercise 16.14. Estimate with 90% confidence the mean electricity consumption for households with four occupants. Data from Exercise 16.14: In an attempt to determine the factors that affect the amount of energy used, 200 households were analyz

> Refer to Exercise 16.13. Predict with 99% confidence the price of a 1999 24-ft. Sea Ray cruiser with 400 hours of engine use. Data from Exercise 16.13: Millions of boats are registered in the United States. As is the case with automobiles, there is an a

> Refer to Exercise 16.12. Estimate with 95% confidence the mean price of 60,000 sq.ft. apartment buildings. Data from Exercise 16.12: A real estate agent specializing in commercial real estate wanted a more precise method of judging the likely selling pr

> Refer to Exercise 16.11. a. Predict with 95% confidence the percentage loss due to fire for a house that is 8 miles away from the nearest fire station. b. Estimate with 95% confidence the average percentage loss due to fire for houses that are 5 miles aw

> Refer to Exercise 16.10. Predict with 95% confidence the number of sick days for individuals who smoke on average 40 cigarettes per day. Data from Exercise 16.10: Besides their known long-term effects, do cigarettes also cause short-term illnesses such

> A professor of statistics hands back his graded midterms in class by calling out the name of each student and personally handing the exam over to its owner. At the end of the process, he notes that there are several exams left over, the result of student

> Refer to Exercise 16.9. The company has just hired a 22-year-old telemarketer. Predict with 95% confidence how long he will stay with the company. Data from Exercise 16.9: The human resource manager of a telemarketing firm is concerned about the rapid t

> Refer to Exercise 16.8. Estimate with 90% confidence the mean amount of time for 40-year-old Americans to complete the census. Data from Exercise 16.8: In 2010, the United States conducted a census of the entire country. The census is completed by mail.

> Refer to Exercise 16.7. a. Predict with 95% confidence the selling price of a 1,200 sq.ft. condominium on the 20 th floor. b. Estimate with 99% confidence the average selling price of a 1,200 sq.ft. condominium on the 15th floor. Data from Exercise 16.7

> Refer to Exercise 16.6. a. Predict with 95% confidence the memory test score of a viewer who watches a 30-second commercial. b. Estimate with 95% confidence the mean memory test score of people who watch 30-second commercials. Data from Exercise 16.6: I

> Refer to Exercise 16.5. Predict with 90% confidence the number of beers to be sold when the temperature is 75 degrees. Data from Exercise 16.5: To help determine how many beers to stock the concession manager at Yankee Stadium wanted to know how the tem

> Refer to Exercise 16.4. a. Predict with 90% confidence the number of pounds overweight for a child who watches 35 hours of television per week. b. Estimate with 90% confidence the mean number of pounds overweight for children who watch 35 hours of televi

> Estimate with 90% confidence the mean monthlynumber of housing starts when the mortgage interest rate is 7% in Exercise 16.3.

> Use the regression equation in Exercise 16.2 to predict with 90% confidence the sales when the advertising budget is $80,000.

> Will the prediction interval always be wider than the estimation interval for the same value of the independent variable? Briefly explain.

> Briefly describe the difference between predicting a value of y and estimating the expected value of y.

> Advertising is critical in the residential real estate industry. Agents are always seeking ways to increase sales through improved advertising methods. A particular agent believes that he can increase the number of inquiries (and thus the probability of

> The president of a company that manufactures drywall wants to analyze the variables that affect demand for his product. Drywall is used to construct walls in houses and offices. Consequently, the president decides to develop a regression model in which t

> Refer to Exercise 17.4. Find the coefficients of correlation of the independent variables. a. What do these correlations tell you about the independent variables? b. What do they say about the t-tests of the coefficients? Data from Exercise 17.4: The ge

> Compute the residuals and predicted values for the regression analysis in Exercise 17.3. a. Does it appear that the error variable is not normally distributed? b. Is the variance of the error variable constant? c. Is multicollinearity a problem?

> Calculate the coefficients of correlation for each pair of independent variables in Exercise 17.1. What do these statistics tell you about the independent variables and the t-tests of the coefficients?