Questions and Answers of Business Statistics A First Course

Suppose that in Problem 13.31, tstat for testing the contribution of X2 is 3.27. At the 0.05 level of significance, is there evidence that X, makes a significant contribution to the model?Data From
In problems 12.8, 12.20, 12.30, 12.46, 12.62, 12.82, and 12.83, you developed regression models to predict franchise value of major league baseball, NBA basketball, and soccer teams. Now, write a
The following results provide the X values, residuals, and a residual plot from a regression analysis:Is there any evidence of a pattern in the residuals? Explain.
1. The Student News Service at Clear Mountain State University (CMSU) has decided to gather data about the undergraduate students that attend CMSU. It creates and distributes a survey of 14 questions
1. Determine whether differences exist in the relationship status (single or partnered), and the self-rated fitness based on the product purchased.2. Write a report to be presented to the management
Phase 1Reviewing the results of its research, the marketing department team concluded that a segment of Ashland households might be interested in a discounted trial subscription to the AMS 3-For-All
Under what conditions should you use the x2 test of independence?
1. The Student News Service at Clear Mountain State University (CMSU) has decided to gather data about the undergraduate students that attend CMSU. It creates and distributes a survey of 14 questions
Referring to the results of Problems 10.85 and 10.86 concerning the weight and granule loss of Boston and Vermont shingles, write a report that summarizes your conclusions.Data From Problem 10.85:The
In Problems 10.39 through 10.41, what is your statistical decision?Data From Problem 10.41:In Problems 10.39 and 10.40, what is the upper-tail critical value for F if the level of significance, α,
In Problems 10.39 and 10.40, what is the upper-tail critical value for F if the level of significance, α, is 0.05 and the alternative hypothesis is H1: σ2/1 ≠ σ2/2?Data From Problem 10.40:In
Referring to Problem 10.2, if n1 = 5 and n2 = 4, how many degrees of freedom do you have?Data From Problem 10.2:Assume that you have a sample of n1 = 8, with the sample mean X̅1 = 42, and a sample
Referring to the results of Problems 9.76 through 9.78 concerning Boston and Vermont shingles, write a report that evaluates the moisture level, weight, and granule loss of the two types of
What is meant by a p-value?
What is the difference between a Type I error and a Type II error?
How do professionals stay on top of their careers? Of 935 surveyed U.S. LinkedIn members, 543 reported that they engaged in professional networking within the last month. (Source: LinkedIn Talent
One of the major measures of the quality of service provided by any organization is the speed with which it responds to customer complaints. A large family-held department store selling furniture and
What is the p-value if, in a two-tail hypothesis test, ZSTAT = −1.38?
What is the p-value if, in a two-tail hypothesis test, ZSTAT = +2.00?
If you use a 0.01 level of significance in a two-tail hypothesis test, what is your decision rule for rejecting H0: μ = 12.5 if you use the Z test?
If you use a 0.10 level of significance in a two-tail hypothesis test, what is your decision rule for rejecting a null hypothesis that the population mean equals 500 if you use the Z test?
In a survey of 239 organizations, 75 responded that “the need for collaboration among increasing number of locations” is a business driver that led them to implement cloud solutions. Cloud
Consider the confidence interval estimate discussed in Problem 8.5. Suppose the population mean time spent on the site is 36 minutes a day. Is the confidence interval estimate stated in Problem 8.5
Is it true in Example 8.1 on that you do not knowfor sure whether the population mean is between 10.9941 and11.0019 inches? Explain.Example 8.1:A paper manufacturer has a production process that
Suppose that step 3 of Problem 7.33 uses the following rule: “If a random digit between 0 and 8 is selected, consider the ball to be white; if a random digit of 9 is selected, consider the ball to
Using a table of random numbers (Table E.1), simulate the selection of different-colored balls from a bowl, as follows:1. Start in the row corresponding to the day of the month in which you were
Why is only one normal distribution table such as Table E.2 needed to find any probability under the normal curve?Table E.2:
What is the meaning of the expected value of a random variable?
The Student News Service at Clear Mountain State University (CMSU) has decided to gather data about the undergraduate students that attend CMSU. CMSU creates and distributes a survey of 14 questions
1. Compute descriptive statistics to create a customer profile for each CardioGood Fitness treadmill product line.2. Write a report to be presented to the management of CardioGood Fitness, detailing
How do the boxplots for the variously shaped distributions differ?
As you have already learned in this book, decision makers use Statistical methods to help analyze data and communicate results. Every day, somewhere, someone misuses these techniques either by
Download and examine the U.S. Census Bureau’s “Business and Professional Classification Survey (SQ-CLASS),” available through the Get Help with Your Form link at www.census.gov/econ/.a. Give an
The Data and Story Library (DASL) is an online library of data files and stories that illustrate the use of basic statistical methods. Visit lib.stat.cmu.edu/index.php, click DASL, and explore a data
A recent PwC Supply Global Chain survey indicated that companies that acknowledge the supply chain as a strategic asset achieve 70% higher performance. The “Leaders” in the survey point to
For a population containing N = 902 individuals, what code number would you assign fora. the first person on the list?b. the fortieth person on the list?c. the last person on the list?
The Data and Story Library (DASL) is an online library of data files and stories that illustrate the use of basic statistical methods. Visit lib.stat.cmu.edu/index.php, click DASL, and explore a data
Referring to the results from Problem 2.100 on page 76 concerning the weights of Boston and Vermont shingles, write a report that evaluates whether the weights of the pallets of the two types of
The Data and Story Library (DASL) is an online library of data files and stories that illustrate the use of basic statistical methods. Go to lib.stat.emu.edu/index.php, click DASL, and explore some
Consider constructing a pie chart for the exam question responses in Exercise 2.4.(a) How many degrees (out of 360) would be assigned to the “pie slice” for the response (a)?(b) How many degrees
Find an estimate of the probability that a randomly selected female aged 16 to 24 is employed, if she is in the civilian labor force and has a bachelor’s degree or more.
If the random variable x is normally distributed, what percentage of all possible observed values of x will bea. Within one standard deviation of the mean?b. Within two standard deviations of the
Why do we compute z values when using the normal table? Explain.
Why do we often need to take a preliminary sample when determining the size of the sample needed to make the margin of error of a confidence interval equal to E?
The accounts of an investment firm have been classified into 143 large accounts, 4,780 medium sized accounts, and 20,973 small accounts. The investment firm provides an auditor with each account’s
Although the department store chain in Example 8.12 has randomly selected 1 percent of the homes in each stratum, there is a more precise way to determine how to sample the strata. The first step is
Explain why we are able to compute many different values of β, the probability of a Type II error, for a single hypothesis test.
Suppose that a spokesman for U.S. travel agencies claims that more than 65 percent of all U.S. passengers who booked cruises last year used travel agencies to book their cruises. In the October 2,
Assume that an insurance survey is based on 1,000 randomly selected U.S. households in a particular income class and finds that 640 of these households bought life insurance last year.a. If p denotes
During 2011 a company implemented a number of policies aimed at reducing the ages of its customers’ accounts. In order to assess the effectiveness of these measures, the company randomly selects 10
In its February 2, 1998, issue, Fortune magazine published the results of a Yankelovich Partners survey of 600 adults that investigated their ideas about marriage and divorce. (All respondents had
Define the meaning of the chi-square points Xa/2 and Xi-(a/2).
Perform pairwise comparisons of the treatment means in Exercise 12.8 by(1) Using Tukey simultaneous 95 percent confidence intervals(2) Optionally using t statistics and critical values (see the right
Explain the difference between the between-treatment variability and the within-treatment variability when performing a one-way ANOVA.
Explain two ways to obtain intervals for a goodness-of-fit test of normality.
Consider testing H0: β1 = 0 versus Ha: β1 ≠ 0. Figure 14.11 tells us that t = 14.44 and that the related p-value is less than .001. Assuming that the bivariate normal probability distribution
We give MINITAB and Excel outputs of simple linear regression analyses of the data sets related to six previously discussed case studies. Using the appropriate computer output,a. Use the explained
We give MINITAB and Excel outputs of simple linear regression analyses of the data sets related to six previously discussed case studies. Using the appropriate computer output,a. Use the explained
The F-test in simple linear regression is equivalent to what other test?
Consider Exercise 5.58, and find if the candy company’s claim is true. If x actually turns out to be 8, what do you think of the claim?Data from Exercise 5.58find if the stain removal product’s
Consider Table 16.13. Verify (calculate) that S3, an estimate made in period 3 of β0, is 359.276. Also verify (calculate) that the one-period-ahead forecast error for period 4 is -62.276, as shown
Figure 16.14 gives the MINITAB output of using simple exponential smoothing to forecast yearly U.S. lumber production. Here MINITAB has estimated the smoothing constant alpha to be .0361553. Use the
The least squares point estimates of the parameters of the tentative hotel room average model are where the MINITAB calculated p-values for the importance of the model parameters are given in
If we fit the model y = β0 + β1x1+ β2x2+ β3x22 + β4x1x2 + ϵ to the real estate sales price data in Table 15.4, we find that the least squares point estimates of the model parameters and
Give an example of a practical application of the confidence interval for βj.
Find an estimate of the probability that a randomly selected female aged 16 to 24 is employed, if she is in the civilian labor force and has a high school degree.
Explain how x relates to the mean m if the z value corresponding to xa. Equals zero.b. Is positive.c. Is negative.
Find the mean of each sample in Exercise 7.12.Data from Exercise 7.12There are six combinations, or samples, of two grand prizes that can be randomly selected from the four grand prizes 20, 40, 60,
There are six combinations, or samples, of two grand prizes that can be randomly selected from the four grand prizes 20, 40, 60, and 80 thousand dollars. Four of these samples are (20, 40), (20, 60),
Suppose that we will randomly select a sample of four measurements from a larger population of measurements. The sampling distribution of the sample mean x̅ is the probability distribution of a
Recall that when the bank manager’s new teller system is operating consistently over time, the manager decides to record the waiting times of a sample of 100 customers that need teller service
Suppose that a population of measurements is normally distributed with mean μ and standard deviation σ.a. Write an expression (involving μ and σ) for a tolerance interval containing 98 percent of
Give two examples of situations in which the exponential distribution might be used appropriately. In each case, define the random variable having an exponential distribution.
Figure 14.35(a) shows the residual plot versus x for the simple linear regression of the laptop service time data. This plot fans out, indicating that the error term e tends to become larger in
The data in Table 14.6 concerning the relationship between smoking and lung cancer death are presented in a course of The Open University, Statistics in Society, Unit C4, The Open University Press,
Using the appropriate model, sample size n, and output:1. Report SSE, s2, and s as shown on the output. Calculate s2 from SSE and other numbers.2. Report the total variation, unexplained variation,
On January 28, 1986, the space shuttle Challenger exploded soon after takeoff, killing all eight astronauts aboard. The temperature at the Kennedy Space Center at liftoff was 31°F. Before the
Using the appropriate model, sample size n, and output:1. Report SSE, s2, and s as shown on the output. Calculate s2 from SSE and other numbers.2. Report the total variation, unexplained variation,
Using the appropriate model, sample size n, and output:1. Report SSE, s2, and s as shown on the output. Calculate s2 from SSE and other numbers.2. Report the total variation, unexplained variation,
Using the appropriate model, sample size n, and output:1. Report SSE, s2, and s as shown on the output. Calculate s2 from SSE and other numbers.2. Report the total variation, unexplained variation,
Sound City sells the True Sound-XL, a top-of-the-line satellite car radio. Over the last 100 weeks, Sound City has sold no radios in three of the weeks, one radio in 20 of the weeks, two radios in 50
Recall that Figure14.26 (a) gives n = 16 weekly values of Pages Bookstore sales (y), Pages advertising expenditure (x1), and competitor’s advertising expenditure (x2). When we fit the model y = β0
Backward elimination is an iterative model selection procedure that begins by considering the model that contains all of the potential independent variables and then attempts to remove independent
What type of trend is indicated by the plot of the deseasonalized data?
Suppose that Table 16.21 gives the yearly automobile operating expenses in a particular region of the United States for the years 1990, 2000, and 2011.a. Using 1990 as the base year, construct the
The Olympia Paper Company, Inc., makes Absorbent Paper Towels. The company would like to develop a prediction model that can be used to give point forecasts and prediction interval forecasts of
Figure 16.30 shows that the sales values in Table 16.22 are nonstationary and non seasonal. At the non seasonal level (lags 1 through 9), the SAC of the regular differences of the sales values has a
Since 1994 a number of consumers have filed and won large claims against national fast-food chains as a result of being scalded by excessively hot beverages such as coffee, tea, and hot chocolate.
Form a group of three or four students in your class. As a group project, select a familiar process and determine a variable that measures the quality of some aspect of the output of this process.
Consider the hot chocolate temperature situation in Exercise 17.9. We found that x̅ and R charts based on subgroups of size 3 for these data are in statistical control with x̅̅ = 140.73 and R̅ =
Find a point forecast and a 95 percent prediction interval for y169.
Explain why it can sometimes be difficult to obtain rational subgroups when using a control chart for fraction nonconforming.
Describe two situations in your personal life in which you might wish to plot a control chart for fraction nonconforming.
Suppose that a product is assembled using 10 different components, each of which must meet specifications for five different quality characteristics. Therefore, we have 50 different specifications
In an issue of Quality Progress, The Juran Institute presents an example that deals with the production of integrated circuits. The article describes the situation as follows: The manufacture of
In an exercise in the book Production/Operations Management, 5th ed. (1996),William ThmPark J. Stevenson considers a theme park whose lease is about to expire. The theme park’s management wishes to
Construct a decision tree for a posterior and preposterior analysis of the control device situation.
In an issue of Quality Progress, Franklin P. Schargel presents a cause-and-effect diagram for the “lack of quality in schools.” We present this diagram in Figure 17.30.a. Identify and circle the
Moore (2000) reports on a study by Boo (1997), who asked 303 randomly selected people at fairs: How often do you think people become sick because of food they consume prepared at outdoor fairs and
Use the following MINITAB output to find rs, and then test H0: px = 0 versus Ha: ps > 0 or the service time data below. Copiers Serviced, x Minutes Required, y 4 109 2 5 7 1 3 58 138 189 37

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