Q39, Page 291

A business executive transferred from Chicago to Atlanta, needs to sell her house in Chicago quickly. The executive's employer has offered to buy the house for $210,000, but the offer expires at the end of the week. The executive does not currently have a better offer but can afford to leave the house on the market for another month. From conversations with her realtor, the executive believes the price she will get by leaving the house on the market for another months is uniformly distributed between $200,000 and $225,000.

a. If she leaves the house on the market for another month, what is the mathematical expression for the probability density function of the sales price?

b. If she leaves it on the marke for another month, what is the probability she will get at least $215,000 for the house?

c. If she leaves it on the market for another month, what is the probability she will get less then $210,000?

d. Should the executive leave the house n the market for another month? Why or why not?

Q47, Page 293

According to Salary Wizard, the average base salary for a brand manager in Houston, Texas, is $88,592 and the average base salary for a brand manager in Los Angeles, California, is $97,417 (Salary Wizard website, February 27, 2008). Assume that salaries are normally distributed, the standard deviation for brand managers in Houston is $19,900 and the standard deviation for brand managers in Los Angeles $21,800.

a. What is the probability that a brand manager in Houston has a base salary in excess of $100,000?

b. What is the probability that a brand manager in Los Angeles has a base salary in excelss of $100,000?

c. What is the probability that a brand manager in Los Angeles has a base salary of less than $75,000?

d. How much would a brand manager in Los Angeles have to make in order to have a higher salary than 99% of the brand managers in Houston?

Show your work below (for full marks) _H = 88,592 _LA = 97,417 _H = 19,900 _LA = 21,800

Q49, Page 293

Consider a multiple-choice examination with 50 questions. Each question has four possible answers. Assume that a student who has done the homework and attended lectures has a 75% probability of answering any question correctly.

a. A student must answer 43 or more questions correctly to obtain a grade of A. What percentage of the students who have done their homework and attended lectures will obtain a grade of A on this multiple-choice examination?

b. A student who answers 35 to 39 questions correctly will receive a grade of C. What percentage of students who have done their homework and attended lectures will obtain a grade of C on this multiple-choice examination?

c. A student must answer 30 or more questions correctly to pass the examination. What percentage of students who have done their homework and attended lectures will pass the examination?

d. Assume that a student has not attended class and has not done the homework for the course. Furthermore, assume that the student will simply guess at the answer to each question. What is the probability that this student will answer 30 or more questions correctly and pass the examination?

Q43, page 335

The latest available data showed health expenditures were $8086 per person in the United States or 17.6% of gross domestic product (Centers for Medicare & Medicaid Services website, April 1, 2012). Use $8086 asthe population mean and suppose a survey research firm will take a samole pf 100 people to investigate the nature of their health expenditures. Assume the popultaion standard deviationis $2500.

a) Show the sampling distribution of the mean amount of health care expenditures for a sample of 100 people.

b)What is the probability that the sample mean x will be within +/- 200 of the population mean m?

c)What is the probability the sample mean will be greater than $9000? If the survey research firm reports asample mean greater than 9000, would you question whether the firm followed correct sampling procedures? Why or why not?

Q47 , page 336

Three firms carry inventories that differ in size. Firm A's inventory contains 2000 items, firm B's inventory contains 5000 items, and firm C's inventory contains 10,000 items. The populationstandard deviation for the cost of the items in each firm's inventory is s =144.

A statistical consultant recommends that each firm take a sample of 50 items from its inventory to provide statistically valid estimates of the average cost per item. Managers of the small firm state that because it has the smallest population, it should be able to make the estimate from a much smallersample than that required by the larger firms. However, the consultant states that to obtain the same standard error and thus the same precision in the sample results, all firms should use the same sample size regardless of population size.

a) Using the finite population correction factor, compute the standard error for each of the three firms given a sample of size 50.

b)What is the probability that for each firm the sample mean x will be within +/- 25 of the population mean m?

Q53, page 337

The proportion of individuals insured by the All-Driver Automobile Insurance Company who received at least one traffic ticket during a five-year period is .15.

a. Show the sampling distribution of p if a random sample of 150 insured individuals is used to estimate the proportion having received at least one ticket.

b.What is the probability that the sample proportion will be within +/- .03 of the population proportion?

Q49 , page 370

A recent article reported that there are approximately 11 minutes of actual playing time in a typical National Football League (NFL) game (The Wall Street Journal, January 15, 2010).The article included information about the amount of time devoted to replays, the amount of time devoted to commercials, and the amount of time the players spend standing around between plays.Use Standing.xlsx file from Datasets folder.

a.Use the Standing dataset to develop a point estimate of the number of minutes during an NFL game that players are standing around between plays. Compare this to the actual playing time reported in the article. Are you surprised?

b.What is the sample standard deviation?

c. Develop a 95% confidence interval for the mean number of minutes players spending standing around between plays.

Q59 , page 372

Workers in several industries were surveyed to determine the proportion of workers who feel their industry is understaffed. In the government sector, 37% of the respondents said they were understaffed, in the health care sector 33% said they were understaffed, and in the education sector 28% said they were understaffed (USA Today, January 11, 2010).

Suppose that 200 workers were surveyed in each industry.

a.Construct a 95% confidence interval for the proportion of workers in each of these industries who feel their industry is understaffed.

b. Assuming the same sample size will be used in each industry, how large would the sample need to be to ensure that the margin of error is 0.05 or less for each of the three confidence intervals?