Question: From 74 of its restaurants, Noodles & Company

> (a) Plot the data on U.S. general aviation shipments. (b) Describe the pattern and discuss possible causes. (c) Would a fitted trend be helpful? Explain. (d) Make a similar graph for 1993–2008 only. Would a fitted trend be helpful in ma

> Which statement is correct? Why not the others? a. Likert scales are interval if scale distances are meaningful. b. Cross-sectional data are measured over time. c. A census is always preferable to a sample.

> (a) Choose one category of consumer credit and plot it. (b) Describe the trend (if any) and discuss possible causes. (c) Fit a trend model of your choice. (d) Make forecasts for 3 years (2011–2013), using a trend model of your choice.

> If freeway speeds are normally distributed with a mean of μ = 70 mph and σ = 7 mph, find the probability that the speed of a randomly chosen vehicle (a) exceeds 78 mph; (b) is between 65 and 75 mph; (c) is less than 70 mph.

> (a) Plot the voter participation rate. (b) Describe the trend (if any) and discuss possible causes. (c) Fit both a linear and a quadratic trend to the data. (d) Which model is preferred? Why? (e) Make a forecast for 2012, using a trend model of your choi

> (a) Plot the total minutes of TV viewing time per household. (b) Describe the trend (if any) and discuss possible causes. (c) Fit a linear trend to the data. (d) Would this model give reasonable forecasts? Would another trend model be better? Explain. (e

> (a) Plot both Swiss watch time series on the same graph. (b) Describe the trend (if any) and discuss possible causes. (c) Fit an exponential trend to each time series. (d) Interpret each fitted trend carefully. What conclusion do you draw? (e) Make forec

> (a) Make a line chart for JetBlue’s revenue. (b) Describe the trend (if any) and discuss possible causes. (c) Fit both a linear and an exponential trend to the data. (d) Which model is preferred? Why? (e) Make annual forecasts for 2011&

> Fertility rates (children born per woman) are shown for 27 EU member nations in 2 years. Research question: At α = .05, is there a significant rank correlation? Only the first 3 and last 3 nations are shown. Fertility Rates in EU Membe

> The table below shows annual financial data for a sample of 20 companies in the food consumer products sector. Research question: At α = .01, is there a significant correlation between revenue and profit? Why is a rank correlation preferred

> In a call center, the average waiting time for an answer (in seconds) is shown below by time of day. Research question: At α = .01, does the waiting time differ by day of the week? Only the first 3 and last 3 observations are shown. Av

> Below are results of braking tests of a certain SUV on glare ice, packed snow, and split traction (one set of wheels on ice, the other on dry pavement), using three braking methods. Research question: At α = .01, is braking method related t

> Mean output of arrays of solar cells of three types are measured four times under random light intensity over a period of 5 minutes, yielding the results shown below. Research question: At α = .05, is the median solar cell output the same f

> Which of the following is not a reason for sampling? Explain. a. The destructive nature of some tests. b. High cost of studying the entire population. c. The expense of obtaining random numbers.

> Does the 95 percent confidence interval for each predictor coefficient include zero? What conclusion can you draw? DATA SET A Mileage and Other Characteristics of Randomly Selected Vehicles (n = 73, k = 4) O Mileage Obs Vehicle CityMPG Len

> The waiting time (in minutes) for emergency room patients with non-life-threatening injuries was measured at four hospitals for all patients who arrived between 6:00 and 6:30 p.m. on a certain Wednesday. The results are shown below. Research question: At

> In a bumper test, three types of autos were deliberately crashed into a barrier at 5 mph, and the resulting damage (in dollars) was estimated. Five test vehicles of each type were crashed, with the results shown below. Research question: At Î&plusm

> Below are grade point averages for 25 randomly chosen university business students during a recent semester. Research question: At α = .01, are the median grade point averages the same for students in these four class levels? Grade Poi

> The square footage of each of the last 11 homes sold in each of two suburban neighborhoods is noted. Research question: At α = .01, do the medians differ? Square Footage of Homes Sold Grosse Hills (Built in 1985) Grosse Hills Haut Nez

> Adult height is somewhat predictable from average height of both parents. For females, a commonly used equation is YourHeight = ParentHeight - 2.5 while for males the equation is YourHeight = ParentHeight + 2.5. (a). Test these equations on yourself an

> Below are results of a regression of Y = average stock returns (in percent) as a function of X = average price/earnings ratios for the period 1949–1997 (49 years). Separate regressions were done for various holding periods (sample sizes

> Below are fitted regressions based on used vehicle ads. Observed ranges of X are shown. The assumed regression model is AskingPrice = f (VehicleAge). (a). Interpret the slopes. (b). Are the intercepts meaningful? Explain. (c). Assess the fit of each

> Below are revenue and profit (both in $ billions) for nine large entertainment companies. (a). Make a scatter plot of profit as a function of revenue. (b). Use Excel to fit the regression, with fitted equation and R2. (c). In your own words, describ

> A common belief among faculty is that teaching ratings are lower in large classes. Below are MINITAB results from a regression using Y = mean student evaluation of the professor and X = class size for 364 business school classes taught during the 2002&ac

> 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, accident data showed 12 repair incidents

> Perform the regression and write the estimated regression equation (round off to 3 or 4 significant digits for clarity). Do the coefficient signs agree with your a priori expectations? DATA SET A Mileage and Other Characteristics of Random

> (a) Interpret the slope of the fitted regression HomePrice = 125,000 + 150 SquareFeet. (b) What is the prediction for HomePrice if SquareFeet = 2,000? (c) Would the intercept be meaningful if this regression applies to home sales in a certain subdivision

> Two manufacturing facilities produce 1280 × 1024 LED (light-emitting diode) displays. Twelve shipments are tested at random from each lab, and the number of bad pixels per billion is noted for each shipment. Research question: At Î&plu

> Simple regression was employed to establish the effects of childhood exposure to lead. The effective sample size was about 122 subjects. The independent variable was the level of dentin lead (parts per million). Below are regressions using various depend

> Choose one of these three data sets. (a) Make a scatter plot. (b) Let Excel estimate the regression line, with fitted equation and R2. (c) Describe the fit of the regression. (d) Write the fitted regression equation and interpret the slope. (e) Do you th

> Consider the following Excel regression of perceived sound quality as a function of price for 27 stereo speakers. (a) Is the coefficient of Price significantly different from zero at α = .05? (b) What does the R2 tell you? (c) Given these r

> Below are fertility rates (average children born per woman) in 15 EU nations for 2 years. (a) Make a scatter plot. (b) Find the correlation coefficient and interpret it. (c) Test the correlation coefficient for significance, clearly stating the degrees o

> 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

> 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

> A forecasting model is fitted to sales data over 24 months. Forecasting errors are tabulated to reveal whether the model provides an overestimate (1) or an underestimate (2) for each month’s sales. The results are - - + + + - + - - + + - - - - - - + + +

> 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.