Business Statistics A Decision Making Approach 8th Edition David F. Groebner, Patrick W. Shannon, Phillip C. Fry, Kent D. Smith - Solutions

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Median versus mean for net worth. A report on the assets of American households says that the median net worth of households headed by someone aged less than 35 years is $11,600. The mean net worth of these same young households is $90,700.30 What explains the difference between these two measures
Carbon dioxide emissions. Table 1.6 (page 26)gives carbon dioxide (CO2) emissions per person for countries with population at least 20 million.The distribution is strongly skewed to the right. The United States and several other countries appear to be high outliers.(a) Give the five-number summary.
Tornados and property damage. Table 1.5 (page 25) shows the average property damage caused by tornadoes over a 50-year period in each of the states.The distribution is strongly skewed to the right.(a) Give the five-number summary. Explain why you can see from these five numbers that the
Outliers in percent of older residents. The stemplot in Exercise 1.21 (page 24) displays the distribution of the percents of residents aged 65 and over in the 50 states. Stemplots help you find the five-number summary because they arrange the observations in increasing order.(a) Give the
College tuition and fees. Figure 1.16 (page 25) is a histogram of the tuition and fees charged by the 56 four-year colleges in the state of Massachusetts.Here are those charges (in dollars), arranged in increasing order:4,123 4,186 4,324 4,342 4,557 4,884 5,397 6,129 6,963 6,972 8,232 13,584 13,612
Luck and puzzle solving. Children in a psychology study were asked to solve some puzzles and were then given feedback on their performance. Then they were asked to rate how luck played a role in determining their scores.29 This variable was recorded on a 1 to 10 scale with 1 corresponding to very
CHALLENGE Vitamin A deficiency in children from Papua New Guinea. In the Papua New Guinea study that provided the data for the previous two exercises, the researchers also measured serum retinol. A low value of this variable can be an indicator of vitamin A deficiency. Below are the data on the
CHALLENGE Transform the blood proteins values.Refer to the previous exercise. With strongly skewed distributions such as this, we frequently reduce the skewness by taking a log transformation.We have a bit of a problem here, however, because some of the data are recorded as 0.00 and the logarithm
Blood proteins in children from Papua New Guinea. C-reactive protein (CRP) is a substance that can be measured in the blood. Values increase substantially within 6 hours of an infection and reach a peak within 24 to 48 hours after. In adults, chronically high values have been linked to an increased
Longleaf pine trees. The Wade Tract in Thomas County, Georgia, is an old-growth forest of longleaf pine trees (Pinus palustris) that has survived in a relatively undisturbed state since before the settlement of the area by Europeans. A study collected data about 584 of these trees.27 One of the
Calculate the points for a student. Use the setting of Example 1.22 to find the points for a student whose score is 950.
A standard deviation of zero. Construct a data set with 5 cases that has a variable with s = 0.
Find the variance and the standard deviation. Here are the scores on the first exam in an introductory statistics course for 10 students:80 73 92 85 75 98 93 55 80 90 Find the variance and the standard deviation for these first-exam scores.
Find the IQR. Here are the scores on the first exam in an introductory statistics course for 10 students:80 73 92 85 75 98 93 55 80 90 Find the interquartile range and use the 1.5 × IQR rule to check for outliers. How low would the lowest score need to be for it to be an outlier according to this
Make a boxplot. Here are the scores on the first exam in an introductory statistics course for 10 students:80 73 92 85 75 98 93 55 80 90 Make a boxplot for these first-exam scores.
Find the five-number summary. Here are the scores on the first exam in an introductory statistics course for 10 students:80 73 92 85 75 98 93 55 80 90 Find the five-number summary for these first-exam scores.
Find the quartiles. Here are the scores on the first-exam in an introductory statistics course for 10 students:80 73 92 85 75 98 93 55 80 90 Find the quartiles for these first-exam scores.
Find the median. Here are the scores on the first exam in an introductory statistics course for 10 students:80 73 92 85 75 98 93 55 80 90 Find the median first-exam score for these students.
Find the mean. Here are the scores on the first exam in an introductory statistics course for 10 students:80 73 92 85 75 98 93 55 80 90 Find the mean first-exam score for these students.
The Boston Marathon. Women were allowed to enter the Boston Marathon in 1972. The following table gives the times (in minutes, rounded to the nearest minute) for the winning women from 1972 to 2006.Year Time Year Time Year Time Year Time 1972 190 1981 147 1990 145 1999 143 1973 186 1982 150 1991
Describe the self-concept scores. Based on a suitable graph, briefly describe the distribution of self-concept scores for the students in Table 1.9. Be sure to identify any suspected outliers.
Describe the IQ scores. Make a graph of the distribution of IQ scores for the seventh-grade students in Table 1.9. Describe the shape, center, and spread of the distribution, as well as any outliers. IQ scores are usually said to be centered at 100. Is the midpoint for these students close to 100,
Grades and self-concept. Table 1.9 presents data on 78 seventh-grade students in a rural midwestern school.25 The researcher was interested in the relationship between the students’ “self-concept”and their academic performance. The data we give here include each student’s grade point
Guinea pigs. Table 1.8 gives the survival times in days of 72 guinea pigs after they were injected with tubercle bacilli in a medical experiment.24 Make a suitable graph and describe the shape, center, and spread of the distribution of survival times. Are there any outliers?
Time spent studying. Do women study more than men? We asked the students in a large first-year college class how many minutes they studied on a typical weeknight. Here are the responses of random samples of 30 women and 30 men from the class:Women Men 180 120 180 360 240 90 120 30 90 200 120 180
The density of the earth. In 1798 the English scientist Henry Cavendish measured the density of the earth by careful work with a torsion balance.The variable recorded was the density of the earth as a multiple of the density of water. Here are Cavendish’s 29 measurements:23 5.50 5.61 4.88 5.07
Oil wells. How much oil the wells in a given field will ultimately produce is key information in deciding whether to drill more wells. Here are the estimated total amounts of oil recovered from 64 wells in the Devonian Richmond Dolomite area of the Michigan basin, in thousands of barrels:22 21.7
Sketch a skewed distribution. Sketch a histogram for a distribution that is skewed to the left. Suppose that you and your friends emptied your pockets of coins and recorded the year marked on each coin.The distribution of dates would be skewed to the left. Explain why.
CHALLENGE Identify the histograms. A survey of a large college class asked the following questions:1. Are you female or male? (In the data, male = 0, female = 1.)2. Are you right-handed or left-handed? (In the data, right = 0, left = 1.)3. What is your height in inches?4. How many minutes do you
CHALLENGE Acidity of rainwater. Changing the choice of classes can change the appearance of a histogram. Here is an example in which a small shift in the classes, with no change in the number of classes, has an important effect on the histogram.The data are the acidity levels (measured by pH)in 105
Thinness in Asia. Asian culture does not emphasize thinness, but young Asians are often influenced by Western culture. In a study of concerns about weight among young Korean women, researchers administered the Drive for Thinness scale (a questionnaire) to 264 female college students in Seoul, South
Fish in the Bering Sea. “Recruitment,” the addition of new members to a fish population, is an important measure of the health of ocean ecosystems. Here are data on the recruitment of rock sole in the Bering Sea between 1973 and 2000:19 Recruitment Recruitment Year (millions) Year
CAUTI ON! Change the scale of the axis. The impression that a time plot gives depends on the scales you use on the two axes. If you stretch the vertical axis and compress the time axis, change appears to be more rapid. Compressing the vertical axis and stretching the time axis make change appear
What do you miss in the histogram? Make a histogram of the mean annual temperatures Pasadena for the years 1951 to 2000. (Data appear in Table 1.7.) Describe the distribution of temperatures. Then explain why this histogram misses very important facts about temperatures in Pasadena.
California temperatures. Table 1.7 contains data on the mean annual temperatures (degrees Fahrenheit) for the years 1951 to 2000 at two locations in California: Pasadena and Redding.18 Make time plots of both time series and compare their main features. You can see why discussions of climate change
Carbon dioxide from burning fuels. Burning fuels in power plants or motor vehicles emits carbon dioxide (CO2), which contributes to global warming.Table 1.6 displays CO2 emissions per person from countries with population at least 20 million.17(a) Why do you think we choose to measure emissions per
APPLE T Use an applet for the tornado damage data. The One-Variable Statistical Calculator applet on the text CD and Web site will make stemplots and histograms. It is intended mainly as a learning tool rather than as a replacement for statistical software. The histogram function is particularly
Tornado damage. The states differ greatly in the kinds of severe weather that afflict them. Table 1.5 24 10 12 14 5 10 15 20 25 30 Tuition and fees ($1000)Number of colleges 86 0FIGURE 1.16 Histogram of the tuition and fees charged by four-year colleges in Massachusetts, for Exercise 1.27.shows the
College tuition and fees. Jeanna plans to attend college in her home state of Massachusetts. She looks up the tuition and fees for all 56 four-year colleges in Massachusetts (omitting art schools and other special colleges). Figure 1.16 is a histogram of the data. For state schools, Jeanna used the
Shakespeare’s plays. Figure 1.15 is a histogram of the lengths of words used in Shakespeare’s plays.Because there are so many words in the plays, we use a histogram of percents. What is the overall shape of this distribution? What does this shape say about word lengths in Shakespeare? Do you
Vocabulary scores of seventh-grade students.Figure 1.14 displays the scores of all 947 seventhgrade students in the public schools of Gary, Indiana, on the vocabulary part of the Iowa Test of Basic Skills.15 Give a brief description of the overall pattern (shape, center, spread) of this
Compare glucose of instruction and control groups. The study described in the previous exercise also measured the fasting plasma glucose of 16 diabetics who were given individual instruction on diabetes control. Here are the data:128 195 188 158 227 198 163 164 159 128 283 226 223 221 220 160 Make
Diabetes and glucose. People with diabetes must monitor and control their blood glucose level. The goal is to maintain “fasting plasma glucose” between about 90 and 130 milligrams per deciliter (mg/dl).Here are the fasting plasma glucose levels for 18 diabetics enrolled in a diabetes control
Split the stems. Make another stemplot of the percent of residents aged 65 and over in the states other than Alaska and Florida by splitting stems 8 to 15 in the plot from the previous exercise. Which plot do you prefer? Why?
An aging population. The population of the United States is aging, though less rapidly than in other developed countries. Here is a stemplot of the percents of residents aged 65 and over in the 50 states, according to the 2000 census. The stems are whole percents and the leaves are tenths of a
Women seeking graduate and professional degrees. The table on the next page gives the percents of women among students seeking various graduate and professional degrees:13(a) Explain clearly why we cannot use a pie chart to display these data.(b) Make a bar graph of the data. (Comparisons are
Spam. Email spam is the curse of the Internet.Here is a compilation of the most common types of spam:12 Type of spam Percent Adult 14.5 Financial 16.2 Health 7.3 Leisure 7.8 Products 21.0 Scams 14.2 Make two bar graphs of these percents, one with bars ordered as in the table (alphabetical) and the
Garbage. The formal name for garbage is“municipal solid waste.” The table at the top of the next column gives a breakdown of the materials that made up American municipal solid waste.11(a) Add the weights for the nine materials given, including “Other.” Each entry, including the total, is
Ages of survey respondents. The survey about color preferences reported the age distribution of the people who responded. Here are the results:Age group (years) 1–18 19–24 25–35 36–50 51–69 70 and over Count 10 97 70 36 14 5(a) Add the counts and compute the percents for each age
Least-favorite colors. Refer to the previous exercise. The same study also asked people about their least-favorite color. Here are the results:orange, 30%; brown, 23%; purple, 13%; yellow, 13%;gray, 12%; green, 4%; white, 4%; red, 1%; black, 0%;and blue, 0%. Make a bar graph of these percents and
Favorite colors. What is your favorite color?One survey produced the following summary of responses to that question: blue, 42%; green, 14%;purple, 14%; red, 8%; black, 7%; orange, 5%; yellow, 3%; brown, 3%; gray, 2%; and white, 2%.10 Make a bar graph of the percents and write a short summary of
Choosing a college or university. Popular magazines rank colleges and universities on their “academic quality” in serving undergraduate students. Describe five variables that you would like to see measured for each college if you were choosing where to study. Give reasons for each of your
Physical fitness of students. You want to measure the “physical fitness” of college students. Describe several variables you might use to measure fitness. What instrument or instruments does each measurement require?
Study habits of students. You are planning a survey to collect information about the study habits of college students. Describe two categorical variables and two quantitative variables that you might measure for each student. Give the units of measurement for the quantitative variables.
What questions would you ask? Refer to the previous exercise. Make up your own survey questions with at least six questions. Include at least two categorical variables and at least two quantitative variables. Tell which variables are categorical and which are quantitative. Give reasons for your
Survey of students. A survey of students in an introductory statistics class asked the following questions: (a) age; (b) do you like to dance? (yes, no); (c) can you play a musical instrument (not at all, a little, pretty well); (d) how much did you spend on food last week? (e) height; (f) do you
Describe the first-exam scores. Refer to the first-exam scores from Exercise 1.5. Use your favorite graphical display to describe the shape, the center, and the spread of these data. Are there any outliers?
Use smaller classes. Repeat the previous exercise using classes 55–59, 60–64, 65–69, etc.
Change the classes in the histogram. Refer to the first-exam scores from Exercise 1.5 and the histogram you produced in Exercise 1.6.Now make a histogram for these data using classes 40–59, 60–79, and 80–100. Compare this histogram with the one that you produced in Exercise 1.6.
Make a histogram. Refer to the first-exam scores from Exercise 1.5.Use these data to make a histogram using classes 50–59, 60–69, etc.Compare the histogram with the stemplot as a way of describing this distribution. Which do you prefer for these data?
Make a stemplot. Here are the scores on the first exam in an introductory statistics course for 30 students in one section of the course:80 73 92 85 75 98 93 55 80 90 92 80 87 90 72 65 70 85 83 60 70 90 75 75 58 68 85 78 80 93 Use these data to make a stemplot. Then use the stemplot to describe the
Read the pie chart. Refer to Figure 1.3(b). What percent of young adults have either an associate degree or a bachelor’s degree?
Apartment rentals. A data set lists apartments available for students to rent. Information provided includes the monthly rent, whether or not cable is included free of charge, whether or not pets are allowed, the number of bedrooms, and the distance to the campus. Describe the individuals or cases
Density Curves and Normal Distributions
Describing Distributions with Numbers
Displaying Distributions with Graphs
Data were collected on a quantitative measure with subgroups of four observations.Twenty-five subgroups were collected, with the following results:x 2.33 R0.80a. Determine the Shewhart factors that will be needed if - and R-charts are to be developed.b. Compute the upper and lower control limits
Data were collected on a quantitative measure with a subgroup size of three observations. Thirty subgroups were collected, with the following results:x 1,345.4 R209.3a. Determine the Shewhart factors that will be needed if - and R-charts are to be developed.b. Compute the upper and lower control
Sid Luka is the service manager for Brakes Unlimited, a franchise corporation that specializes in servicing automobile brakes. He wants to study the length of time required to replace the rear drum brakes of automobiles. A subgroup of 10 automobiles needing their brakes replaced was selected on
Susan Booth is the director of operations for National Skyways, a small commuter airline with headquarters in Cedar Rapids, Iowa. She has become increasingly concerned about the amount of carry-on luggage passengers have been carrying on board National Skyways’ planes. She collected data
Recall from Exercise 18-20 that Tony Perez is the manager of one of the largest chains of service stores that specialize in oil and lubrication of automobiles, Fastlube, Inc. One of the company’s stated goals is to provide a lube and oil change for anyone’s automobile in 15 minutes. Tony has
Regis Printing Company performs printing services for individuals and business customers. Many of the jobs require that brochures be folded for mailing. The company has a machine that does the folding. It generally does a good job, but it can have problems that cause it to do improper folds. To
Referring to Exercise 18-23, if necessary delete any out-of-control points and construct the appropriate -and R-charts. Now, suppose the process stays in control for the next six weeks (subgroups 18 through 23). The subgroup means and ranges for subgroups 33 to 38 are as follows:Subgroup 33 34 35
The Kaiser Corporation makes aluminum at various locations around the country. One of the key factors in being profitable is keeping the machinery running.One particularly troublesome machine is a roller that flattens the sheets to the appropriate thickness. This machine tends to break down for
Referring to Exercise 18-21, assume the Ajax managers determine any issues identified by the control charts were caused by one time events. The data for weeks 41 through 45 are in the Ajax-Extra file.a. Using the control limits developed from the first 40 weeks, do these data indicate that the
Wilson, Ryan, and Reed is a large certified public accounting (CPA) firm in Charleston, South Carolina.It has been monitoring the accuracy of its employees and wishes to get the number of accounts with errors under statistical control. It has sampled 100 accounts for each of the last 30 days and
Referring to the process control charts developed in Exercise 18-14, data for periods 31 to 40 are contained in the file Grandfoods-Extra.a. Based on these data, what would you conclude about the energy bar process?b. Write a report discussing the results, and show the control charts along with the
Referring to Exercise 18-15, suppose the process remained in control for the next 40 hours.The thickness measurements for hours 41 through 43 are as follows:Hour 41 0.764 0.737 0.724 0.716 0.752 Hour 42 0.766 0.785 0.777 0.790 0.799 Hour 43 0.812 0.774 0.767 0.799 0.821a. Based on these data and
Explain why it is important to update the control charts as soon as new data become available.Computer Database Exercises
Data were collected on a quantitative measure with a subgroup size of five observations. Thirty subgroups were collected, with the following results:x 44.52 R5.6a. Determine the Shewhart factors that will be needed if - and R-charts are to be developed.b. Compute the upper and lower control
The city bus line is consistently running behind schedule. Brainstorm possible causes organized by such cause categories as people, methods, equipment, and the environment. Once you have finished, develop a priority order based on which cause is most likely to be the root cause of the problem.
Suppose the computer lab manager at your school has been receiving complaints from students about long waits to use a computer. The “effect” is long wait times. The categories of possible causes are people, equipment, methods/rules, and the environment.Brainstorm specific ideas for each of
Refer to Exercise 18-6.a. Use brainstorming to generate a list of solutions for the top-rated parking problem.b. Order these possible solutions separately according to each of the following factors: cost to implement, time to implement, and easiest to gain approval.c. Did your lists come out in a
Assume that you are a member of a team at your university charged with the task of improving student, faculty, and staff parking. Use brainstorming to generate a list of problems with the current parking plan. After you have generated the list, prioritize the list of problems based on their
Generate a process flowchart showing the steps you have to go through to buy a concert ticket at your school.
Develop a process flowchart that describes the registration process at your college or university.
Philip Crosby wrote the book Quality Is Free. In it he argues that it is possible to have high quality and low price. Do you agree? Provide examples that support your position.Business Applications
Deming is opposed to setting quotas or specific targets for workers.a. Use the library or the Internet to locate information that explains his reasoning.b. Discuss whether you agree or disagree with him.c. If possible, cite one or more examples based on your own experience to support your position.
Discuss the similarities and differences between Dr. Deming’s 14 points and Dr. Juran’s 10 steps to quality improvement.
Two brands of tires are being tested for tread wear. To control for vehicle and driver variation, one tire of each brand is put on the front wheels of 10 cars. The cars are driven under normal driving conditions for a total of 15,000 miles. The tread wear is then measured using a very sophisticated
A Vermont company is monitoring a process that fills maple syrup bottles. When the process is filling correctly, the median average fill in an 8-ounce bottle of syrup is 8.03 ounces. The last 15 bottles sampled revealed the following levels of fill:7.95 8.02 8.07 8.06 8.05 8.04 7.97 8.01 8.04 8.05
During the production of a textbook, there are many steps between when the author begins preparing the manuscript and when the book is finally printed and bound. Tremendous effort is made to minimize the number of errors of any type in the text. One type of error that is especially difficult to
The manager of credit card operations for a small regional bank has determined that last year’s median credit card balance was $1,989.32. A sample of 18 customer balances this year revealed the following figures, in dollars:Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 1,827.85 1,992.75
A study was recently conducted by the Bonneville Power Association (BPA) to determine attitudes regarding the association’s policies in western U.S. states. One part of the study asked respondents to rate the performance of the BPA on its responsiveness to environmental issues.The following
The Style-Rite Company of Atlanta makes windbreaker jackets for people who play golf and who are active outdoors during the spring and fall months.The company recently developed a new material and is in the process of test-marketing jackets made from the material. As part of this test-marketing
The Miltmore Corporation performs consulting services for companies that think they have image problems. Recently, the Bluedot Beer Company approached Miltmore. Bluedot executives were concerned that the company’s image, relative to its two closest competitors, had diminished. Miltmore conducted
The Hunter Family Corporation owns roadside diners in numerous locations across the country. For the past few months, the company has undertaken a new advertising study. Initially, company executives selected 22 of its retail outlets that were similar with respect to sales volume, profitability,
Students attending West Valley Community College buy their textbooks online from one of two different book sellers because the college does not have a bookstore. The following data represent sample amounts that students spend on books per term:Company 1 ($) Company 2 ($)246 300 211 305 235 308 270
Let us examine how the sampling distribution of the Wilcoxon test statistic is obtained. Consider the sampling distributions of the positive ranks from a sample size of 4. The ranks to be considered are, therefore, 1, 2, 3, and 4. Under the null hypothesis, the differences to be ranked are
Students attending West Valley Community College buy their textbooks online from one of two different book sellers because the college does not have a bookstore. The following data represent sample amounts that students spend on books per term:Calculate this value for n1 2 and n2 3. Now

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Business Statistics A Decision Making Approach 8th Edition David F. Groebner, Patrick W. Shannon, Phillip C. Fry, Kent D. Smith - Solutions

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