Question: Students applying for admission to an MBA
Students applying for admission to an MBA program must submit scores from the GMAT test, which includes a verbal and a quantitative component. Shown here are raw scores for 100 randomly chosen MBA applicants at a Midwestern, public, AACSB-accredited business school. Research question: At α = .005, is the quantitative score independent of the verbal score?
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Quantitative Verbal Under 25 25 to 34 35 or More Row Total Under 25 25 1 35 25 to 34 4 28 18 50 35 or More 1 3 11 15 Col Total 30 40 30 100
> Why is the quality improvement process never-ending? Identify the steps of one improvement cycle identified in the textbook.
> (a) What determines sampling frequency? (b) Why are variable samples often small? (c) Why are attribute samples often large?
> What is the difference between an attribute control chart and a variable control chart?
> Which statement is true for a normal distribution? Why not the others? a. The shape of the PDF is always symmetric regardless of μ and σ. b. The shape of the CDF resembles a bell-shaped curve. c. When no tables are available, areas may be found by a sim
> Name the survey instrument used to measure service quality. What are the five service quality dimensions?
> Which statement is false? Explain. a. In the hypergeometric distribution, sampling is done without replacement. b. The mean of the uniform distribution is always (a + b)/2. c. We use the geometric distribution to find probabilities of arrivals per unit o
> Identify three common quality improvement programs and give their acronyms.
> Explain the difference between SQC and SPC.
> Which data type (categorical, numerical) is each of the following? a. Your current credit card balance. b. Your college major. c. Your car’s odometer mileage reading today.
> Which statement is correct for a simple regression? Why not the others? a. A 95% confidence interval (CI) for the mean of Y is wider than the 95% CI for the predicted Y. b. A confidence interval for the predicted Y is widest when X =. c. The t test for
> The price of a particular stock over a period of 60 days rises (1) or declines (2) in the following pattern. Research question: At α = .05, is the pattern random? + + - - - + + + + + + + - - - - + + - + - + - + - - - - + + + + - + + + + - + + + - + - + -
> Explain the role of statisticians in quality improvement.
> On the Internet, look up two influential thinkers in quality control, and briefly state their contributions.
> Which statement is true? Why not the others? a. The Poisson distribution has two parameters. b. The binomial distribution assumes dependent random trials. c. The uniform distribution has two parameters.
> Can zero variation be achieved? Explain.
> Explain the difference between common cause variation and special cause variation.
> Match each statement to the correct property of an estimator (unbiased, consistent, efficient): a. The estimator “collapses” on the true parameter as n increases. b. The estimator has a relatively small variance. c. The expected value of the estimator i
> Which type of probability (empirical, classical, subjective) is each of the following? a. On a given Friday, the probability that Flight 277 to Chicago is on time is 23.7%. b. Your chance of going to Disney World next year is 10%. c. The chance of rolli
> Define a measurable aspect of quality for (a) the car dealership where you bought your car, (b) the bank or credit union where you usually make personal transactions, and (c) the movie theater where you usually go.
> Look up two of Deming’s 14 points on the Internet and explain their meaning.
> Explain the relationship between productivity and quality from a modern perspective. How does this differ from the past perspective?
> Thirty-four customers at Starbucks either ordered coffee (C) or did not order coffee (X). Research question: At α = .05, is the sequence random? C X C X C C C C X X X X C X C X C X C C C X C X C C X C X X X C C X
> Which statement is not correct concerning a p-value? Explain. a. Ceteris paribus, a larger p-value makes it more likely that H0 will be rejected. b. The p-value shows the risk of Type I error if we reject H0 when H0 is true. c. In making a decision, we
> List four rules for detecting abnormal (special cause) observations in a control chart.
> (a) To construct control limits for an chart, name three ways to estimate σ empirically. (b) Why is the method often used? (c) Why is the s method the default in MINITAB?
> Samples are shown of volatility (coefficient of variation) for sector stocks over a certain period of time. (a). At α = .05, is there a difference in median volatility in these four portfolios? Use Mega- Stat, MINITAB, or a similar compu
> An experimental bumper was designed to reduce damage in low-speed collisions. This bumper was installed on an experimental group of vans in a large fleet, but not on a control group. At the end of a trial period, there were 12 repair incidents (a “repair
> Bob and Tom are “paper investors.” They each “buy” stocks they think will rise in value and “hold” them for a year. At the end of the year, they c
> Final exam scores for a sample of 20 students in a managerial accounting class are shown. (a). At α = .05, is there a difference in the population median scores on the two exams? Make an Excel worksheet for your Wilcoxon signed-rank test
> A sample of 28 student scores on the chemistry midterm exam is shown. (a). At α = .10, does the population median differ from 50? Make a worksheet in Excel for your calculations. (b). Make a histogram of the data. Would you be justified
> A baseball player was at bat 33 times during preseason exhibition games. His pattern of hits (H) and nonhits (N) is shown (a nonhit is a walk or a strikeout). Research question: At = 5 .01, is the pattern of hits random? N N N H N H N N H N N H H N N N N
> On a professional certifying exam, there are 25 true-false questions. The correct answers are T F T T F F F T T F T F T T T F F T T F F T T F T. Research question: At α = .05, is the T/F pattern random?
> Which data would be most suitable for a pie chart? Why not the others? a. Presidential vote in the last election by party (Democratic, Republican, Other). b. Retail prices of six major brands of color laser printers. c. Labor cost per vehicle for 10 maj
> Using α = .10, perform a runs test for randomness on the sample data (n = 24). X O X X X X O O O O X O O O X O O O X O O X X O
> Weights of 12 randomly chosen Sonora Bars (a type of candy) from assembly line 1 had a mean weight of 56.25 grams (g) with a standard deviation of 0.65 g, while the weights of 12 randomly chosen Sonora Bars from assembly line 2 had a mean weight of 56.75
> Rates of return on 24 mutual funds are shown. (a) Convert the data to ranks. Check the column sums. (b) Calculate Spearman’s rank correlation coefficient. Show your calculations. (c) At α = .01 can you reject the hypothesi
> Profits of 20 consumer food companies are shown. (a) Convert the data to ranks. Check the column sums. (b) Calculate Spearman’s rank correlation coefficient. Show your calculations. (c) At α = .01 can you reject the hypoth
> JavaMax is a neighborhood take-out coffee shop that offers three sizes. Yesterday’s sales are shown. Use MegaStat or another software package to perform a Friedman test to see whether the median sales of coffee sizes differ at Î&p
> Consumers are asked to rate the attractiveness of four potential dashboard surface textures on an interval scale (1 5 least attractive, 10 5 most attractive). Use MegaStat or another software package to perform a Friedman test to see whether the median r
> The results shown below are mean productivity measurements (average number of assemblies completed per hour) for a random sample of workers at each of three work stations. (a). At α = .05, is there a difference in median productivity? Us
> Using α = .05, perform a runs test for randomness on the sample data (n = 27). A A B B A A B B A B A A B B B A A B B B B A A B A B B
> One-year sales volume of four similar 20-oz. beverages on a college campus is shown. Beverage ………………………………………………………. Sales (Cases) Frappuccino Coffee ………………………………………………………... 18 Frappuccino Mocha ………………………………………………………… 23 Frappuccino Vanilla …………………………
> Advertisers need to know which age groups are likely to see their ads. Purchasers of 120 copies of Cosmopolitan are shown by age group. Purchaser Age ………………………………………………. Units Sold 18–24 ……………………………………………….………………………. 38 25–34 ……………………………………………….…………………
> Use MegaStat or MINITAB to identify observations with high leverage. Midterm and Final Exam Scores for Business Statistics Students Fall Semester 2011 (n = 58 students) Midterm Exam Score ………&
> Market research has shown that Americans will continue to eat out even in a depressed economy. A market analysis during the most recent recession showed the following distribution of visits to the various types of restaurants: A new survey of 250 Ameri
> U.S. market share for smartphones with larger screens is increasing. As of the first quarter of 2011, smartphones with screens 4 inches or larger had captured 24 percent of the smartphone market. The market for smartphones with screens between 3.5 and 3.
> Last month, 85 percent of the visitors to the Sonora Candy Factory made a purchase in the on-site candy shop after taking the factory tour. This month, a random sample of 500 such visitors showed that 435 purchased candy after the tour. The manager said,
> Marketing researchers sent an advance e-mail notice announcing an upcoming Internet survey and describing the purpose of their research. Half the target customers received the prenotification, followed by the survey. The other half received only the surv
> Is HDTV ownership related to quantity of purchases of othe r electronics? A Best Buy retail outlet collected the following data for a random sample of its recent customers. Research question: At α = .10, is the frequency of in-store purchas
> Teenagers make up a large percentage of the market for clothing. Below are data on running shoe ownership in four world regions (excluding China). Research question: At α = .01, does this sample show that running shoe ownership depends on w
> Use MINITAB’s Stat > Basic Statistics > Normality Test or other software to obtain a probability plot for the exam score data (see Exercise 15.15). Interpret the probability plot and Anderson-Darling statistic. Exercise 15.15: E
> One Friday night, there were 42 carry-out orders at Ashoka Curry Express. (a). Estimate the mean and standard deviation from the sample. (b). Assuming that the data are from a normal distribution, define bins by using method 3 (equal expected frequen
> Exam scores of 40 students in a statistics class are shown. (a). Estimate the mean and standard deviation from the sample. (b). Assuming that the data are from a normal distribution, define bins by using method 3 (equal expected frequencies). Use 8 b
> Use MegaStat or MINITAB to generate 95 percent confidence and prediction intervals for various X-values. Midterm and Final Exam Scores for Business Statistics Students Fall Semester 2011 (n = 58 students) Midterm Exam Score …â
> At a local supermarket receiving dock, the number of truck arrivals per day is recorded for 100 days. (a). Estimate the mean from the sample. (b). Calculate the expected frequencies assuming a Poisson distribution. Show your calculations in a spreads
> During the 1973–74 hockey season, the Boston Bruins played 39 home games and scored 193 points, as shown below. (a). Estimate the mean from the sample. (b). Calculate the expected frequencies assuming a Poisson distribution. Show yo
> Excel was asked to generate 50 Poisson random numbers with mean λ = 5. X ……………………………………………………………….. Frequency 0 ……………………………………………………………………………….. 1 1 ……………………………………………………………………………….. 1 2 ……………………………………………………………………………….. 4 3 ……………………………………………………………………………
> Which statement is correct? Why not the others? a. The level of significance α is the probability of committing Type I error. b. As the sample size increases, critical values of t.05 increase, gradually approaching z.05. c. When σ is unknown, it is conse
> Ages of 56 attendees of a recent Hunger Games movie are shown. (a). Form seven age classes (10 to 20, 20 to 30, etc.). Tabulate the frequency of attendees in each class. (b). Calculate expected frequencies for each class. (c). Perform a chi-square G
> In a three-digit lottery, each of the three digits is supposed to have the same probability of occurrence (counting initial blanks as zeros, e.g., 32 is treated as 032). The table shows the frequency of occurrence of each digit for 90 consecutive daily t
> A random sample of California residents who had recently visited a car dealership were asked which type of vehicle they were most likely to purchase, with the results shown. Research question: At α = .10, is the choice of vehicle type indep
> (a) Use MegaStat or MINITAB to deseasonalize the monthly Corvette sales data and fit a trend. Interpret the results. (b) Use MegaStat or MINITAB to perform a regression using seasonal binaries. Interpret the results. (c) Use the regression equation to ma
> (a) Use MegaStat or MINITAB to deseasonalize the quarterly data on PepsiCo’s revenues and fit a trend. Interpret the results. (b) Use MegaStat or MINITAB to perform a regression using seasonal binaries. Interpret the results. (c) Use th
> (a) Make an Excel line graph of the following bond yield data. Describe the pattern. Is there a consistent trend? (b) Use exponential smoothing (MegaStat, MINITAB, or Excel) with α = .20. Use both methods A and B to initialize the forecast
> Is an autocorrelation test appropriate for your data? If so, perform an eyeball inspection of residual plot against observation order or a runs test. Midterm and Final Exam Scores for Business Statistics Students Fall Semester 2011 (n = 58 students) Mi
> (a) Make an Excel line graph of the exchange rate data. Describe the pattern. (b) Click on the data and choose Add Trendline > Moving Average. Describe the effect of increasing m (e.g., m = 2, 4, 6, etc.). Include a copy of each graph with your answer
> (a) Plot the data on fruit and vegetable consumption. (b) Discuss the underlying causes that might explain the trend or pattern. (c) Fit a linear trend to the data. (d) Interpret the trend equation. What are its implications for producers? (e) Make a for
> (a) Make an Excel line graph of the car dealership data. (b) Discuss the underlying causes that might explain the trend or pattern. (c) Fit three trends (linear, exponential, quadratic). (d) Would any of the three trend models yield adequate forecasts? E
> (a) Make an Excel line graph of the data on employee work stoppages. (b) Discuss the underlying causes that might explain the trend or pattern. (c) Fit three trends (linear, exponential, quadratic). (d) Which trend model is best, and why? If none is sati
> In the previous problem, find (a) the 95th percentile of waiting times (i.e., 95 percent below); (b) the first quartile of waiting times; (c) the mean time between arrivals.
> (a) Make an Excel graph of the data on the number of certified organic farms in the United States. (b) Discuss the underlying causes that might explain the trend or pattern. (c) Use Excel, MegaStat, or MINITAB to fit three trends (linear, quadratic, expo
> In 2009, US Airways Flight 1549 made a successful emergency landing in the Hudson River, after striking birds shortly after takeoff. Are bird strikes an increasing threat to planes? (a). Make an Excel graph of the data on bird strikes. (b). Discuss t
> Refer to the ANOVA table below. (a) State the degrees of freedom for the F test for overall significance. (b) Use Appendix F to look up the critical value of F for α = .05. (c) Calculate the F statistic. Is the regression significant overal
> Refer to the ANOVA table below. (a) State the degrees of freedom for the F test for overall significance. (b) Use Appendix F to look up the critical value of F for α = .05. (c) Calculate the F statistic. Is the regression significant overal
> Refer to the ANOVA table below. (a) State the degrees of freedom for the F test for overall significance. (b) Use Appendix F to look up the critical value of F for α = .05. (c) Calculate the F statistic. Is the regression significant overal
> Inspect the residual plot to check for heteroscedasticity and report your conclusions. Midterm and Final Exam Scores for Business Statistics Students Fall Semester 2011 (n = 58 students) Midterm Exam Score ……&aci
> A regression model to predict Y, the state-by-state 2005 burglary crime rate per 100,000 people, used the following four state predictors: X1 = median age in 2005, X2 = number of 2005 bankruptcies per 1,000 people, X3 = 2004 federal expenditures per capi
> Vail Resorts asked a random sample of guests to rate their satisfaction on various attributes of their visit on a scale of 1–5 with 1 = very unsatisfied and 5 = very satisfied. The estimated regression model was Y = overall satisfaction score, X1 = lift
> Which violations of regression assumptions, if any, do you see in these residual diagnostics? Explain. Normal Probability Plot Versus Predicted Y 99 1 90 50 -1 10 -2 1 1 -1.5 -1.0 -0.5 0.0 Residual Fitted Value Histogram Runs Plot versus Order 3 -1
> Which would be “high leverage” observations? a. Leverage hi = .15 in a regression with 5 predictors and 72 observations. b. Leverage hi = .18 in a regression with 4 predictors and 100 observations. c. Leverage hi = .08 in a regression with 7 predictors
> Using the “Vail Guest Satisfaction Survey” data, construct a correlation matrix of the 11 independent variables. The response variable is ovalue. (a). Identify the four pairs of independent variables that have the highest pairwise correlation values. D
> If arrivals follow a Poisson distribution with mean 1.2 arrivals per minute, find the probability that the waiting time until the next arrival will be (a) less than 1.5 minutes; (b) more than 30 seconds; (c) between 1 and 2 minutes.
> The same data set from exercise 13.19 also has gender information for each engineer. The binary variable Male = 1 indicates the engineer is male and Male = 0 indicates the engineer is female. Run the regression with Salary as the response variable and Ye
> Observations are taken on sales of a certain mountain bike in 30 sporting goods stores. The regression model was Y = total sales (thousands of dollars), X1 = display floor space (square meters), X2 5= competitors’ advertising expenditures (thousands of d
> The data set below shows a sample of salaries for 39 engineers employed by the Solnar Company along with each engineer’s years of experience. (a). Construct a scatter plot using Salary as the response variable and Years as the explan
> A model was developed to predict the length of a sentence (the response variable) for a male convicted of assault using the following predictor variables: age (in years), number of prior felony convictions, whether the criminal was married or not (1 = ma
> (a). Make a histogram (or normal probability plot) of the residuals and discuss its appearance. (b). Do you see evidence that your regression may violate the assumption of normal errors? Midterm and Final Exam Scores for Business Statistics Students Fa
> State you’re a priori hypothesis about the sign of the slope. Is it reasonable to suppose a cause and effect relationship? Midterm and Final Exam Scores for Business Statistics Students Fall Semester 2011 (n = 58 students) Midterm Exa
> Is the sample size sufficient to yield a good estimate? If not, do you think more data could easily be obtained, given the nature of the problem? Midterm and Final Exam Scores for Business Statistics Students Fall Semester 2011 (n = 58 students) Midter
> How do you imagine the data were collected? Midterm and Final Exam Scores for Business Statistics Students Fall Semester 2011 (n = 58 students) Midterm Exam Score …………&acir
> Are the variables cross-sectional data or time-series data? Midterm and Final Exam Scores for Business Statistics Students Fall Semester 2011 (n = 58 students) Midterm Exam Score ………â
> A basketball player took 35 free throws during the season. Her sequence of hits (H) and misses (M) is shown. Research question: At α = .01, is her hit/miss sequence random? H M M H H M H M M H H H H H M M H H M M H M H H H M H H H H M M M H H
> A supplier of laptop PC power supplies uses a control chart to track the output (in watts) of each unit produced. The pattern below shows whether each unit’s output was above (A) or below (B) the desired specification. Research question: At α = .05, do t
> Below are the top 20 U.S. football teams in the seventh and eighth weeks of a recent season, along with the points awarded to each team by a poll of coaches. Research question: At α = .01, based on these data, does the true rank correlation
> Are gasoline prices a potential policy tool in controlling carbon emissions? The table below shows 2001 gasoline prices (dollars per liter) and carbon dioxide emissions per dollar of GDP. Research question: At α = .05, based on these data,
> The management of a theme park obtained a random sample of the ages of 36 riders of its Space Adventure Simulator. (a). Make a nice histogram. (b). Did your histogram follow Sturges’ Rule? If not, why not? (c). Describe the distrib
> The table below shows ratings of 18 movies by two reviewers (on a 0 to 5 ✰ scale using half ✰ increments). Research question: At α = .05, based on these data, is the rank correlation between reviewers signi
> A newspaper article listed nutritional facts for 56 frozen dinners. From that list, 16 frozen dinners were randomly selected by using the random number method. Research question: Choose any two variables. At α = .01, based on this sample, i
> (a) Use MegaStat or MINITAB to perform a regression using seasonal binaries. Interpret the results. (b) Make monthly forecasts for 2010. If you can find data on the web, check your forecasts. Student Pilot Certificates Issued by Month, 2004-2009 Mon
> (a) Use MegaStat or MINITAB to deseasonalize the quarterly data on Coca-Cola’s revenues and fit a trend. Interpret the results. (b) Use MegaStat or MINITAB to perform a regression using seasonal binaries. Interpret the results. (c) Use
