Question: A forecasting model is fitted to sales

> Below are percentages for annual sales growth and net sales attributed to loyalty card usage at 74 Noodles & Company restaurants. (a) Make a scatter plot. (b) Find the correlation coefficient and interpret it. (c) Test the correlation coefficient for

> Do stock prices of competing companies move together? Below are daily closing prices of two computer services firms (IBM = International Business Machines Corporation, HPQ = Hewlett- Packard Company. (a) Calculate the sample correlation coefficient (e.g.

> In the following regression, X = total assets ($ billions), Y = total revenue ($ billions), and n = 64 large banks. (a) Write the fitted regression equation. (b) State the degrees of freedom for a two tailed test for zero slope, and use Appendix D to fin

> In the following regression, X = monthly maintenance spending (dollars), Y = monthly machine downtime (hours), and n = 15 copy machines. (a) Write the fitted regression equation. (b) State the degrees of freedom for a two-tailed test for zero slope, and

> Does your sample size fulfill Evans’ Rule (n/k > 10) or at least Doane’s Rule (n/k > 5)? DATA SET A Mileage and Other Characteristics of Randomly Selected Vehicles (n = 73, k = 4) O Mileage Obs Veh

> In the following regression, X = weekly pay, Y = income tax withheld, and n = 35 McDonald’s employees. (a) Write the fitted regression equation. (b) State the degrees of freedom for a two tailed test for zero slope, and use Appendix D t

> (a) Make a scatter plot of the data. What does it suggest about the correlation between X and Y? (b) Use Excel, MegaStat, or MINITAB to calculate the correlation coefficient. (c) Use Excel or Appendix D to find t.025 for a two-tailed test at Î&plu

> Bob said, “We use the normal distribution to set the control limits for the
chart because samples from processes follow a normal distribution.” Is Bob right? Explain.

> Based on the cost of sampling and the presumed accuracy required, would sampling or 100 percent inspection be used to collect data on (a) the horsepower of each engine being installed in new cars; (b) the fuel consumption per seat mile of each Northwest

> Two contingency tables below show return on investment (ROI) and percent of sales growth over the previous 5 years for 85 U.S. firms. ROI is defined as percentage of return on a combination of stockholders’ equity (both common and prefe

> In a study of childhood asthma, 4,317 observations were collected on education and smoking during pregnancy, shown in the 4 × 3 contingency table below. Research question: At α = .005, is smoking during pregnancy independent of

> Forecasters’ interest rate predictions over an eight-year period were studied to see whether the predictions corresponded to what actually happened. The 2 × 2 contingency table below shows the frequencies of actual and pred

> High levels of cockpit noise in an aircraft can damage the hearing of pilots who are exposed to this hazard for many hours. A Boeing 727 co-pilot collected 61 noise observations using a handheld sound meter. Noise level is defined as “L

> Choose either 2 × 2 contingency table shown below (males or females). Research question: At α = .005, is smoking independent of race? (Smoking rates are from Statistical Abstract of the United States, 2001, pp. 16 and 12, appli

> A student team examined parked cars in four different suburban shopping malls. One hundred vehicles were examined in each location. Research question: At α = .05, does vehicle type vary by mall location? (Data are from a project by MBA stud

> State your a priori hypotheses about the sign (+ or -) of each predictor and your reasoning about cause and effect. Would the intercept have meaning in this problem? Explain. DATA SET A Mileage and Other Characteristics of Randomly Selecte

> A web-based anonymous survey of students asked for a self-rating on proficiency in a language other than English and the student’s frequency of newspaper reading. Research question: At α = .10, is frequency of newspaper re

> From 74 of its restaurants, Noodles & Company managers collected data on per-person sales and the percent of sales due to “potstickers” (a popular food item). Both numerical variables failed tests for normality, so

> A sample of 200 customers at a supermarket showed that 28 used a debit card to pay for their purchases. (a). Find the 95 percent confidence interval for the population proportion. (b). Why is it OK to assume normality in this case? (c). What sample siz

> To see whether students who finish an exam first get the same grades as those who finish later, a professor kept track of the order in which papers were handed in. Of the first 25 papers, 10 received a “B” or better, c

> Sixty-four students in an introductory college economics class were asked how many credits they had earned in college, and how certain they were about their choice of major. Research question: At α = .01, is the degree of certainty independ

> Employees of Axolotl Corporation were sampled at random from pay records and asked to complete an anonymous job satisfaction survey, yielding the tabulation shown. Research question: At α = .05, is job satisfaction independent of pay catego

> Moisture content per gram of a certain baked product has specification limits of 120 mg and 160 mg. Find the Cp and Cpk capability indexes if (a) the process mean is 140 mg and the process standard deviation is 5 mg; and (b) the process mean is 140 mg an

> In painting an automobile, the thickness of the color coat has a lower specification limit of 0.80 mil and an upper specification limit of 1.20 mils. Find the Cp and Cpk capability indexes if (a) the process mean is 1.00 mil and the process standard devi

> A process has specification limits of LSL = 540 and USL = 550. The process standard deviaton is σ = 1.25. Find the Cp and Cpk capability indexes if (a) the process mean is 545; (b) the process mean is 543.

> Define three quality metrics that might be used to describe quality and performance for the following services: (a) your cellular phone service (e.g., Verizon); (b) your Internet service provider (e.g., AOL); (c) your dry cleaning and laundry service; (d

> Are the X and Y data well-conditioned? If not, make any transformations that may be necessary and explain. DATA SET A Mileage and Other Characteristics of Randomly Selected Vehicles (n = 73, k = 4) O Mileage Obs Vehicle CityMPG Length Widt

> Define three possible quality metrics (not necessarily the ones actually used) to describe and monitor: (a) your performance in your college classes; (b) effectiveness of the professors in your college classes; (c) your effectiveness in managing your per

> Explain each chart’s purpose and the parameters that must be known or estimated to establish its control limits. a.
chart b. R chart c. p chart d. I chart

> Pick one Excel data set (A through F) and investigate whether the data could have come from a normal population using α = .01. Use any test you wish, including a histogram, or MegaStat’s Descriptive Statistics > Normal

> (a) Make a scatter plot of the data. What does it suggest about the correlation between X and Y? (b) Use Excel, MegaStat, or MINITAB to calculate the correlation coefficient. (c) Use Excel or Appendix D to find t.025 for a two-tailed test at Î&plu

> The table below shows the number of ATM customer arrivals per minute in 60 randomly chosen minutes. Research question: At α = .025, can you reject the hypothesis that the number of arrivals per minute follows a Poisson process? 0 0 1 3

> In the World Cup tournaments between 1990 and 2002, there were 232 games with the distribution of goals shown in this worksheet. Research question: At α = .025, can you reject the hypothesis that goals per game follow a Poisson process? You

> A student rolled a supposedly fair die 60 times, resulting in the distribution of dots shown. Research question: At α = .10, can you reject the hypothesis that the die is fair? Number of Dots 1 2 3 5 6. Total Frequency 7 14 13 7 10 60

> In a four-digit lottery, each of the four digits is supposed to have the same probability of occurrence. The table shows the frequency of occurrence of each digit for 89 consecutive daily four digit drawings. Research question: At α = .01, can you reject

> Oxnard Kortholt, Ltd., employs 50 workers. Research question: At α = .05, do Oxnard employees differ significantly from the national percent distribution? Oxnard Employees Frequency National Health Care Visits Percentage No visits 16.5

> Prof. Green’s multiple-choice exam had 50 questions with the distribution of correct answers shown below. Research question: At α = .05, can you reject the hypothesis that Green’s exam answers came from a uniform population? Correct Answer …………………………………

> Are these cross-sectional data or time-series data? What is the unit of observation (e.g., firm, individual, year)? DATA SET A Mileage and Other Characteristics of Randomly Selected Vehicles (n = 73, k = 4) O Mileage Obs Vehicle CityMPG Le

> Make a scatter plot of Y against X. Discuss what it tells you. Midterm and Final Exam Scores for Business Statistics Students Fall Semester 2011 (n = 58 students) Midterm Exam Score ………â

> The actual distribution of car colors for 2006 model car buyers is shown below. Based on the sample of 200 car buyers for 2012 model vehicles, use the multinomial chi-square GOF test at α = .05 to test whether car buyers’

> A survey of 189 statistics students asked the age of car usually driven and the student’s political orientation. The car age was a numerical variable, which was converted into ordinal categories. Research question: At α =

> A survey of randomly chosen new students at a certain university revealed the data below concerning the main reason for choosing this university instead of another. Research question: At α = .01, is the main reason for choosing the univers

> Can people really identify their favorite brand of cola? Volunteers tasted Coke, Pepsi, Diet Coke, and Diet Pepsi, with the results shown below. Research question: At α = .05, is the correctness of the prediction different for regular cola

> Driving without a seat belt is not risky. I’ve done it for 25 years without an accident.” This best illustrates which fallacy? a. Unconscious bias. b. Conclusion from a small sample. c. Post hoc reasoning.

> Researchers found a correlation coefficient of r = .50 on personality measures for identical twins. A reporter interpreted this to mean that “the environment orchestrated one-half of their personality differences.” Do you agree with this interpretation?

> A researcher used stepwise regression to create regression models to predict CarTheft (thefts per 1,000) using four predictors: Income (per capita income), Unem (unemployment percent), Pupil/ Tea (pupil-to-teacher ratio), and Divorce (divorces per 1,000

> For a multiple regression, which statement is true? Why not the others? a. Evans’ Rule suggests at least 10 observations for each predictor. b. The tcalc in a test for significance of a binary predictor can have only two values. c. Occam’s Razor says we

> Make a fishbone chart (cause-and-effect diagram) for the reasons an airline flight might be late to arrive. Use as many branches as necessary. Which factors are most important? Which are most easily controlled? Flight Is Late Arriving at Destination

> Make a fishbone chart (cause-and-effect diagram) for the reasons your end-of-month checkbook balance may not match your bank statement. Use as many branches as necessary. Which factors are most important? Which are most easily controlled? Checkbook

> Make a fishbone chart (cause-and-effect diagram) like the following for the reasons you have ever been (or could be) late to class. Use as many branches as necessary. Which factors are most important? Which are most easily controlled? Late Arrival t

> Why are p charts widely used in service applications like health care?

> Which is not an ethical obligation of a statistician? Explain. a. To know and follow accepted procedures. b. To ensure data integrity and accurate calculations. c. To support client wishes in drawing conclusions from the data.

> To choose a sample of 12 students from a statistics class of 36 students, which type of sample (simple random, systematic, cluster, convenience), is each of these? a. Picking every student who was wearing blue that day. b. Using Excel’s =RANDBETWEEN (1,

> Tell if each variable is continuous or discrete. a. Tonnage carried by an oil tanker at sea. b. Wind velocity at 7 o’clock this morning. c. Number of text messages you received yesterday.

> Which statement is incorrect? Explain. a. The triangular always has a single mode. b. The mean of the triangular is (a + b + c)/3. c. The triangular cannot be skewed left or right.

> Which is not a characteristic of using a log scale to display time series data? Explain. a. A log scale helps if we are comparing changes in two time series of dissimilar magnitude. b. General business audiences find it easier to interpret a log scale.

> Give the type of measurement (nominal, ordinal, interval, ratio) for each variable. a. Length of time required for a randomly chosen vehicle to cross a toll bridge. b. Student’s ranking of five cell phone service providers. c. The type of charge card us

> Tell if each statement is true or false for a simple regression. If false, explain. a. If the standard error is syx = 3,207, then a residual ei = 4,327 would be an outlier. b. In a regression with n = 50, then a leverage statistic hi = .10 indicates unu

> Describe two quality improvement tools unique to the service industry.

> In a study of stock prices from 1970 to 1994, the correlation between Nasdaq closing prices on successive days (i.e., with a 1-day lag) was r = .13 with a t statistic of 5.47. Interpret this result. (See David Nawrocki, “The Problems with Monte Carlo Sim

> 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