Consider the
> Why is it much more difficult to establish independence than it is to establish dependence (lack of independence)?
> Here are the numbers of new customers who signed up for full service during each quarter of last year: 106, 108, 72, and 89. a. How many would you have expected to see in each quarter if these customers had signed up at exactly the same rate throughout t
> Use the data sets from problems 2 and 3, on profit as a percent of sales for building materials firms and for aerospace firms. a. Find the median profit for each industry group and compare them. b. Combine the two data sets into a single column of profit
> a. Describe the data set consisting of two unpaired samples. b. What hypotheses would ordinarily be tested for such data?
> What is the purpose of the chi-squared test for independence?
> a. What assumption must be met for the sign test to be valid? b. What assumption is not required for the sign test but would be required for a t test to be valid?
> a. What is meant by independence of two qualitative variables? b. What is the relationship between conditional probabilities and independence of qualitative variables?
> Can statistical process control be applied to business activities in general, or is it restricted to manufacturing?
> What is the purpose of the chi-squared test for equality of percentages?
> a. What is a parametric statistical method? b. Name some parametric methods you have used.
> For what kind of variables are chi-squared tests useful?
> Describe the similarities and differences between the sign test for the differences and the paired t test.
> a. How should you interpret this statement: One test is more efficient than another? b. If the distribution is normal, which would be more efficient, a parametric test or a nonparametric test? c. If the distribution is far from normal, which would be lik
> a. List the advantages of nonparametric testing over parametric methods, if any. b. List the disadvantages, if any, of nonparametric testing compared with parametric methods. How serious are these shortcomings?
> Your human resources department has referred 26 employees for alcohol counseling. While the work habits of 15 improved, 4 actually got worse, and the remaining 7 were unchanged. Use the sign test for the differences to tell whether significantly more peo
> a. What does the chi-squared statistic measure, in terms of the relationship between the observed data and the null hypothesis? b. Do you reject the null hypothesis for large or for small values of the chi-squared statistic? Why?
> a. What is a nonparametric statistical method? b. For the nonparametric approach based on counts, what is being counted? What probability distribution is used to make the decision? c. For the nonparametric approach based on ranks, what information is dis
> a. Describe a typical control chart for a process that is in control. b. Describe three different ways in which a control chart could tell you that the process is not in control.
> a. What is a control chart? b. Explain how control charts help you perform the five basic activities of statistics. c. What hypotheses are being tested when you use control charts? d. What is the false alarm rate? Is it conventional to set it at 5%?
> a. What information is displayed in a Pareto diagram? b. What makes the Pareto diagram useful as a management tool?
> a. What do we mean when we say that a process is in a state of statistical control? b. What should you do when a process is not in control? c. What should you do when a process appears to be in control?
> a. What is an assignable cause of variation? b. What is a random cause of variation?
> a. What kind of data set is appropriate for the sign test for the differences? b. What hypotheses are being tested? c. What assumption is required?
> Why should you monitor a process? Why not just inspect the results and throw away the defective ones?
> a. What is a process? b. What is the relationship between a process and its sub processes? c. What is statistical process control?
> a. What is the purpose of the percentage chart? b. How large should the sample size be? c. How would you find the center line if you had no standard? d. How would you find the centerline if you did have a standard? e. How would you find the control limit
> Stress levels were recorded during a true answer and a false answer given by each of six people in a study of lie-detecting equipment, based on the idea that the stress involved in telling a lie can be measured. The results are shown in Table 16.4.4. a.
> a. What is the purpose of the R chart? b. What is a typical sample size? c. How would you find the center line if you had no standard? d. How would you find the centerline if you did have a standard? e. How would you find the control limits if you had no
> a. What is the purpose of the
> a. What is statistical quality control? b. Why are statistical methods so helpful for quality control?
> a. For the chi-squared test for independence, what do you conclude if the chi-squared statistic is larger than the value in the chi-squared table? b. What do you conclude if the chi-squared statistic is smaller than the value in the chi-squared table?
> a. For what kind of data set is the chi-squared test for independence appropriate? b. What are the reference values for this test, if any? c. What are the hypotheses? d. How are the expected counts obtained? What do they represent? e. What assumptions ar
> a. For the chi-squared test for equality of percentages, what do you conclude if the chi-squared statistic is larger than the value in the chi-squared table? b. What do you conclude if the chi-squared statistic is smaller than the value in the chi-square
> No matter how closely the production process is monitored, some chips will work faster than others and be worth more in the marketplace. The goal is to make this number as high as possible, and improvements are being implemented continually. Consider the
> a. Can the sign test for the differences be used with quantitative data? Why or why not? b. Can the sign test for the differences be used with ordinal data? Why or why not? c. Can the sign test for the differences be used with nominal data? Why or why no
> Describe the similarities and differences between the sign test and the t test.
> a. For what kind of data set is the chi-squared test for equality of percentages appropriate? b. What are the reference values for this test? c. What are the hypotheses? d. How are the expected counts obtained? What do they represent? e. What assumptions
> a. Can the sign test be used with quantitative data? Why or why not? b. Can the sign test be used with ordinal data? Why or why not? c. Can the sign test be used with nominal data? Why or why not?
> a. For a continuous population, which measure of typical value is the sign test concerned with? b. What probability distribution does this test rely on? c. Suppose the population is discrete and an appreciable fraction of the population is equal to its m
> Consider the profits of the building materials firms in the Fortune 500, given in Table 16.4.1. a. Draw a histogram of these profit percentages. Describe the distribution. b. Find the average and the median. Explain why they are either similar or differe
> For each of the following situations, say whether parametric or nonparametric methods would be preferred. Give a reason for your choice and indicate how serious a problem it would be to use the other method. a. Your data set consists of bond ratings, of
> Use an on parametric test to see whether the median experience of employees differs significantly from 3 years.
> Last year your department handled a median of 63,821 calls per day. (This is the median of the total calls handled each day during the year.) So far this year, more than half of the days have had total calls above this level (there were 15 days above and
> Of the 35 people in your sales force, more than half have productivity above the national median. The exact numbers are 23 above and 12 below. Are you just lucky, or is your sales force significantly more productive than the national median? How do you k
> Consider the profits of the aerospace firms in the Fortune 500, shown in Table 16.4.2. a. Draw a histogram of these profit percentages. Describe the distribution. b. Find the average and the median. Explain why they are either similar or different. c. Us
> Mr. K. R. Wood, president of Broccoli Enterprises, is interested in the data shown in Table 18.5.4, representing the lengths of broccoli trees after cutting. a. Find the average,
> Continue with the data set in Table 18.5.3, representing the thicknesses of a protective coating. a.* Find the center line for the R chart. b.* Find the control limits for the R chart. c. Draw the R chart. d. Comment on what you see in the R chart. In pa
> Consider the data set shown in Table 18.5.3, representing the thicknesses of a protective coating. a. Find the average,
> Find the center line and control limits for each of the following situations. a.*
> A firm specializing in the processing of rebate certificates has tabulated the frequency of occurrence of various types of problems, as shown in Table 18.5.2. a. Arrange the problems in order from most to least frequent, and create a table indicating the
> A candy manufacturer has observed the frequency of various types of problems that occur in the production of small chocolates with a hard candy coating. The basic data set is shown in Table 18.5.1. a. Arrange the problems in order from most to least freq
> Use a nonparametric test to see whether the median age of employees differs significantly from 40 years.
> What problems, if any, are visible in the control charts in Fig. 18.5.7? What action (if any) would you suggest? Fig. 18.5.7: 15 25 20 - 10 AM 15 - 10 - 5- 10 15 20 25 5 10 15 20 25 FIG. 18.5.7 Averages Ranges
> A tractor manufacturing plant has been experiencing problems with the division that makes the transmissions. A Pareto diagram, shown in Fig. 18.5.1, has been constructed based on recent experience. a. What is the most important problem, in terms of the n
> Find the probability that a particular set of eight consecutive points will fall on one side of the center line for a process that is in control.
> Consider the data set shown in Table 18.5.7, indicating hourly summaries of the temperature for a baking oven measured four times per hour. a. Draw an
> Consider the data set shown in Table 18.5.5, summarizing recent numbers of errors in batches of 500 invoices. a. Find the percentage, p, for each batch. b. Find the average percentage,
> Find the center line and control limits for each of the following situations. a.* Percentage chart, sample size n¼300,
> Continue with the data set in Table 18.5.4, representing the lengths of broccoli trees after cutting. a. Find the center line for the R chart. b. Find the control limits for the R chart. c. Draw the R chart. d. Comment on what you see in the R chart. In
> For each of the following situations, tell whether a Pareto diagram, an X chart, an R chart, or a percentage chart would be the most helpful. Give a reason for your choice. a.* Your workers all want to be helpful, but they cannot seem to agree on which
> Refer to the data for problem 8. a. What does the null hypothesis of independence claim, in practical terms, for this situation? b. How many stockholders responding “Very likely” would you expect to find in this sample
> Use a nonparametric test to see whether the distribution of annual salaries for men differs significantly from the distribution for women.
> Consider the results of a small opinion poll concerning the chances of another stock market crash in the next 12 months comparable to the crash of 1987, shown in Table 17.4.4. a. Fill in the “Total” row and column. b.
> Refer to the data for problem 5. a. Find the critical value from the chi-squared table for the 5% level and report the result of the chisquared test. b. Find the critical value from the chi-squared table for the 1% level and report the result of the chis
> Refer to the data for problem 5. a. What does the null hypothesis of independence claim, in practical terms, for this situation? b. How many managers responding “Worse” would you expect to find in this sample if respon
> Your firm is considering expansion to a nearby city. A survey of employees in that city, asked to respond to the question “Will business conditions in this area get better, stay the same, or get worse?” produced the da
> Out of 267 roller skates randomly selected for close examination, 5 were found to have a loose rivet, and 12 were not cleaned according to specifications. a. Use the formula for computing an expected count. How many roller skates would you expect to have
> Last year at this time, your firm’s incoming telephone calls followed the percentages shown in Table 17.4.2. a. Find the percentages for the first day of this month and compare them to last year’s percentages for this
> For each potential customer entering an auto showroom, the type of vehicle desired is recorded. Table 17.4.1 shows data for the past week, together with percentages for the past year at this time. a. Find the percentages for last week’s
> One group of households was asked how satisfied they were with their car, while the other group was asked how dissatisfied they were. Results are shown in Table 17.4.7. a. Which group was more likely to report that they were satisfied? b. Which group was
> The eastern factory had 28 accidents last year, out of a workforce of 673. The western factory had 31 accidents during this time period, out of 1,306 workers. a. Which factory had more accidents? Which factory had a greater accident rate? b. Is there a s
> Does it really matter how you ask a question? A study was conducted that asked whether or not people would pay $30 to eat at a particular restaurant.6 One group was told “there is a 50 percent chance that you will be satisfied,” while the other was told
> Is there evidence consistent with gender discrimination in training level? To answer this, proceed as follows: a. Create a table of counts for the two qualitative variables “gender” and “training level.” b. Compute the overall percentage table and commen
> A commercial bank is reviewing the status of recent real estate mortgage applications. Some applications have been accepted, some rejected, and some are pending while waiting for further information. The data are shown in Table 17.4.6 and graphed in Fig.
> A mail-order company is interested in whether or not “order rates” (the percent of catalogs mailed that result in an order) vary from one region of the country to another. Table 17.4.5 gives recent data on the number o
> Refer to the data for problem 8. a. Find the critical value from the chi-squared table for the 5% level and report the result of the chisquared test. b. Find the critical value from the chi-squared table for the 1% level and report the result of the chis
> a. If an observed count is 3 and the expected count is 8.61, is there any problem with going ahead with a chi-squared test? b. If an observed count is 8 and the expected count is 3.29, is there any problem with going ahead with a chi-squared test?
> Perform a nonparametric analysis of prescription drug prices in the United States and Canada, as reported in Table 16.4.7. a. Is this a paired or unpaired situation? b. Are prices significantly higher in the United States? How do you know? Table 16.4.7
> The number of items returned for each of the past 9 days was 13, 8, 36, 18, 6, 4, 39, 47, and 21. Test to see if the median number returned is significantly different from 40 and find the p-value (as either p>0.05, p
> Are tasting scores significantly different for the Chardonnay and Cabernet-Sauvignon wines listed in Table 10.7.6? Is this a paired or unpaired situation? Table 10.7.6: TABLE 10.7.6 Wine-Tasting Scores Cabernet Cabernet Expert Chardonnay Sauvignon
> Would there be any problem with a nonparametric analysis (two unpaired samples) of data listing day care rates comparing those of the well-to-do Laurelhurst area to other parts of Seattle? Why or why not?
> To understand your competitive position, you have examined the reliability of your product as well as the reliability of your closest competitor’s product. You have subjected each product to abuse that represents about a yearâ
> Your firm is being sued for gender discrimination, and you are evaluating the documents filed by the other side. Their data set is shown in Table 16.4.5. a. Draw box plots for this data set on the same scale and comment on their appearance. b.* Use a non
> Do training levels A, B, and C have approximately the same number of employees, except for randomness? (To answer this, test whether the percentage of employees at each training level differs significantly from the proportions 1/3, 1/3, and 1/3 for the t
> Although Clif Bar & Company is not a public company, it does share its financial information with its employees as part of its open-book management approach. Further, although it does not publicly share its financial information, it does provide a differ
> Some people are tempted to make their finances look worse to get financial aid. Companies sometimes also manage their financial numbers in order to accomplish certain goals. Earnings management is the planned timing of revenues, expenses, gains, and loss
> Amy Sawyer, the bookkeeper for New Hampshire Company, has been trying to determine the correct balance sheet for the company. The company’s balance sheet is shown below. Instructions Explain to Amy Sawyer in a memo why the original ba
> Anya and Nick Ramon, local golf stars, opened the Chip-Shot Driving Range on March 1, 2020, by investing $25,000 of their cash savings in the business. A caddy shack was constructed for cash at a cost of $8,000, and $800 was spent on golf balls and golf
> This exercise will familiarize you with the skills needed (other than accounting skills) to be a successful accountant. Instructions Search the Internet for “start here go places” to access free accounting resources for future CPAs and then answer the f
> Amazon.com, Inc.’s financial statements are presented in Appendix D. Financial statements of Wal-Mart Stores, Inc. are presented in Appendix E. The complete annual reports of Amazon and Wal-Mart, including the notes to the financial sta
> PepsiCo, Inc.’s financial statements are presented in Appendix B. Financial statements of The Coca-Cola Company are presented in Appendix C. The complete annual reports of PepsiCo and Coca-Cola, including the notes to the financial stat
> Selected journal entries for the Walt Bryce Company are presented in BE2.7. Post the transactions using the standard form of account. Journal Entries from BE 2.7: J1 Date Account Titles and Explanation Ref. Debit Credit May 5 Accounts Receivable 5,
> The financial statements of Apple Inc. for 2015 are presented in Appendix A. The complete annual report, including the notes to the financial statements, is available at the company’s website. Instructions Refer to Appleâ€&#
> Auditors provide a type of certification of corporate financial statements. Certification is used in many other aspects of business as well. For example, it plays a critical role in the sustainability movement. The February 7, 2012, issue of the New York
> Every company needs to plan in order to move forward. Its top management must consider where it wants the company to be in three to five years. Like a company, you need to think about where you want to be three to five years from now, and you need to sta
> Melia’s Maid Company off ers home-cleaning service. Two recurring transactions for the company are billing customers for services performed and paying employee salaries. For example, on March 15, bills totaling $6,000 were sent to customers and $2,000 wa
> Summarized operations for Bayles Co. for the month of July are as follows. Revenues recognized: for cash $20,000; on account $70,000. Expenses incurred: for cash $26,000; on account $40,000. Indicate for Bayles Co. (a) the total revenues, (b) the total e
> Bayler Enterprises had a capital balance of $186,000 at the beginning of the period. At the end of the accounting period, the capital balance was $189,000. a. Assuming no additional investment or withdrawals during the period, what is the net income for
> Selected transactions from the journal of June Feldman, investment broker, are presented below. Instructions a. Post the transactions to T-accounts. b. Prepare a trial balance at August 31, 2020. Date Account Titles and Explanation Ref. Debit Credi
> In February 2020, Ola Gott invested an additional $12,000 in her business, Gott’s Pharmacy, which is organized as a proprietorship. Gott’s accountant, Sal Costa, recorded this receipt as an increase in cash and revenues. Is this treatment appropriate? Wh
