New Semester Started Get 50% OFF Study Help! --h --m --s Claim Now

Question Answers

Textbooks

Find textbooks, questions and answers

Oops, something went wrong!

Change your search query and then try again

Result Not Found

Books FREE
Study Help
Tutors
AI Study Planner NEW
Sell Books

Search
Sign In
Register

study help
business
business statistics communicating

Introduction To The Practice Of Statistics 6th Edition David S. Moore, George P. McCabe, Bruce A. Craig - Solutions

Can you change attitudes toward binge drinking?A experiment designed to change attitudes about binge drinking is to be performed using college students as subjects. Discuss some variables that you might use if you were to use a block design for this experiment.
Evaluate a new teaching method. A teaching innovation is to be evaluated by randomly assigning students to either the traditional approach or the new approach. The change in a standardized test score is the response variable. Explain how this experiment should be done in a double-blind fashion.
What is wrong? Explain what is wrong with each of the following randomization procedures and describe how you would do the randomization correctly.(a) A list of 50 subjects is entered into a computer file and then sorted by last name. The subjects are assigned to five treatments by taking the first
What is needed? Explain what is deficient in each of the following proposed experiments and explain how you would improve the experiment.(a) Two forms of a lab exercise are to be compared.There are 10 rows in the classroom. Students who sit in the first 5 rows of the class are given the first form,
Do the randomization. Use computer software to carry out the randomization in Example 3.13.
Diagram the food for Mars experiment. Refer to Exercise 3.11 (page 179). Draw a diagram similar to Figure 3.3 that describes the food for space travel experiment.
Diagram the drawing experiment. Refer to Exercise 3.12 (page 180).Draw a diagram similar to Figure 3.3 that describes the computer graphics drawing experiment.
Does using statistical software improve exam scores? An instructor in an elementary statistics course wants to know if using a new statistical software package will improve students’ final-exam scores.He asks for volunteers and about half of the class agrees to work with the new software. He
Learning how to draw. A course in computer graphics technology requires students to learn multiview drawing concepts. This topic is traditionally taught using supplementary material printed on paper. The instructor of the course believes that aWeb-based interactive drawing program will be more
Food for a trip to the moon. Storing food for long periods of time is a major challenge for those planning for human space travel beyond the moon. One problem is that exposure to radiation decreases the length of time that food can be stored. One experiment examined the effects of nine different
Find an experiment. Use the Internet or some printed material to find an example of an experiment that interests you. Describe how the experiment was conducted and some of the conclusions.
Software for teaching biology. An educational software company wants to compare the effectiveness of its computer animation for teaching cell biology with that of a textbook presentation. The company tests the biological knowledge of each of a group of first-year college students, then randomly
Violent acts on prime-time TV. A typical hour of prime-time television shows three to five violent acts. Linking family interviews and police records shows a clear association between time spent watching TV as a child and later aggressive behavior.4(a) Explain why this is an observational study
Cell phones and brain cancer. One study of cell phones and the risk of brain cancer looked at a group of 469 people who have brain cancer.The investigators matched each cancer patient with a person of the same sex, age, and race who did not have brain cancer, then asked about use of cell phones.3
Find a sample survey. Use the Internet or some printed material to find an example of a sample survey that interests you. Describe the population, how the sample was collected, and some of the conclusions.
Find some available data. Visit the Internet and find an example of available data that is interesting to you. Explain how the data were collected and what questions the study was designed to answer.
Automobile seat belts. When the discussion turns to the pros and cons of wearing automobile seat belts, Herman always brings up the case of a friend who survived an accident because he was not wearing a seat belt. The friend was thrown out of the car and landed on a grassy bank, suffering only
Preference for Jolt Cola. Jamie is a hard-core computer programmer.He and all his friends prefer Jolt Cola (caffeine equivalent to two cups of coffee) to either Coke or Pepsi (caffeine equivalent to less than one cup of coffee).1 Explain why Jamie’s experience is not good evidence that most young
Describe an example. Find an example from some recent experience where anecdotal evidence is used to draw a conclusion that is not justified.Describe the example and explain why it cannot be used in this way.
Final Fu. Your friends are big fans of “Final Fu,” MTV2’s martial arts competition. To what extent do you think you can generalize your preferences for this show to all students at your college?
CHALLENGE Health conditions and risk behaviors.The data set BRFSS described in the Data Appendix gives several variables related to health conditions and risk behaviors as well as demographic information for the 50 states and the District of Columbia. Pick at least three pairs of variables to
CHALLENGE Athletes and gambling. A survey of student athletes that asked questions about gambling behavior classified students according to the National Collegiate Athletic Association(NCAA) division.69 For male student athletes, the percents who reported wagering on collegiate sports are given
Identity theft. A study of identity theft looked at how well consumers protect themselves from this increasingly prevalent crime. The behaviors of 61 college students were compared with the behaviors of 59 nonstudents.68 One of the questions was “When asked to create a password, I have used
Age of the intended readership. The ads in the study described in the previous exercise were also classified according to the age group of the intended readership. Here is a summary of the data:Magazine readership age group Model clothing Young adult Mature adult Not sexual (percent) 72.3%
Sexual imagery in magazine ads. In what ways do advertisers in magazines use sexual imagery to appeal to youth? One study classified each of 1509 full-page or larger ads as “not sexual” or“sexual,” according to the amount and style of the clothing of the male or female model in the ad.The
CH ALLENGE Class size and class level. A university classifies its classes as either “small”(fewer than 40 students) or “large.” A dean sees that 62% of Department A’s classes are small, while Department B has only 40% small classes.She wonders if she should cut Department A’s budget
Construct an example with four schools. Refer to the previous exercise. Make up a similar table for a hypothetical university having four different schools that illustrates the same point. Carefully summarize your table with the appropriate percents.
An example of Simpson’s paradox. Mountain View University has professional schools in business and law. Here is a three-way table of applicants to these professional schools, categorized by gender, school, and admission decision:66 Business Law Admit Admit Gender Yes No Gender Yes No Male 400 200
CHALLENGE Look at volunteers only. Refer to the previous exercise. Recompute the table for volunteers only. To do this, take the entries for each motivation and divide by the percent of volunteers. Do this separately for each gender.Verify that the percents sum to 100% for each gender. Give a
CHALLENGE Motivation to participate in volunteer service. A study examined patterns and characteristics of volunteer service for young people from high school through early adulthood.65 Here are some data that can be used to compare males and females on participation in unpaid volunteer service or
University degrees in Asia. Asia has become a major competitor of the United States and Western Europe in education as well as economics.Following are counts of first university degrees in science and engineering in the three regions:64 Region United Western Field States Europe Asia Engineering
SAT scores and grade point averages. Can we predict college grade point average from SAT scores and high school grades? The CSDATA data set described in the Data Appendix contains information on this issue for a large group of computer science students. We will look only at SAT Mathematics scores
CHALLENGE Midterm-exam scores and final-exam scores. We expect that students who do well on the midterm exam in a course will usually also do well on the final exam. Gary Smith of Pomona College looked at the exam scores of all 346 students who took his statistics class over a 10-year period.63 The
Firefighters and fire damage. Someone says,“There is a strong positive correlation between the number of firefighters at a fire and the amount of damage the fire does. So sending lots of firefighters just causes more damage.” Explain why this reasoning is wrong.
Stock prices in Europe and the U.S. The same article that claims that the correlation between changes in stock prices in Europe and the United States was 0.8 in 2000 goes on to say: “Crudely, that means that movements on Wall Street can explain 80% of price movements in Europe.” Is this true?
Global investing. One reason to invest abroad is that markets in different countries don’t move in step. When American stocks go down, foreign stocks may go up. So an investor who holds both bears less risk. That’s the theory. Now we read:“The correlation between changes in American and
CHALL ENGE Wood flakes as a building material.Wood scientists are interested in replacing solid-wood building material by less expensive products made from wood flakes. They collected the following data to examine the relationship between the length (in inches) and the strength(in pounds per square
CH ALLENGE Marine bacteria and X-rays. Expose marine bacteria to X-rays for time periods from 1 to 15 minutes. Here are the number of surviving bacteria (in hundreds) on a culture plate after each exposure time:60 Time Count Time Count Time Count 1 355 6 106 11 36 2 211 7 104 12 32 3 197 8 60 13 21
Running speed and stride rate. The following table gives data on the relationship between running speed (feet per second) and stride rate(steps taken per second) for elite female runners.59 Speed 15.86 16.88 17.50 18.62 19.97 21.06 22.11 Stride rate 3.05 3.12 3.17 3.25 3.36 3.46 3.55 Here are the
Solar heating panels and gas consumption.To study the energy savings due to adding solar heating panels to a house, researchers measured the natural-gas consumption of the house for more than a year, then installed solar panels and observed the natural-gas consumption for almost two years. The
Asian culture and thinness. 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
Distribution of the residuals. Some statistical methods require that the residuals from a regression line have a Normal distribution.The residuals for the nonexercise activity example are given in Exercise 2.83 (page 127). Is their distribution close to Normal? Make a Normal quantile plot to find
CH ALLENGE Plywood strength. How strong is a building material such as plywood? To be specific, support a 24-inch by 2-inch strip of plywood at both ends and apply force in the middle until the strip breaks. The modulus of rupture (MOR) is the force needed to break the strip. We would like to be
CH ALLENGE Monkey calls. The usual way to study the brain’s response to sounds is to have subjects listen to “pure tones.” The response to recognizable sounds may differ. To compare responses, researchers anesthetized macaque monkeys. They fed pure tones and also monkey calls directly to
Stock prices and earnings. In the long run, the price of a company’s stock ought to parallel changes in the company’s earnings. Table 2.8 gives data on the annual growth rates in earnings and in stock prices (both in percent) for major industry groups as set by Standard & Poor’s.55(a) Make a
Endangered animals and habitat. Endangered animal species often live in isolated patches of habitat. If the population size in a patch varies a lot (due to weather, for example), the species is more likely to disappear from that patch in a bad year. Here is a general question: Is there less
CHALLENGE Look at the data for men. Refer to the previous exercise. Analyze the data for the men’s team from the same college and compare your results with those for the women.
CHALLENGE Points scored in women’s basketball games. Use the Internet to find the scores for the past season’s women’s basketball team at a college of your choice. Is there a relationship between the points scored by your chosen team and the points scored by the opponent?Summarize the data
Predicting text pages. The editor of a statistics text would like to plan for the next edition. A key variable is the number of pages that will be in the final version. Text files are prepared by the authors using a word processor called LATEX, and separate files contain figures and tables. For the
CH ALLENGE Eating fruits and vegetables and education. Refer to the previous exercise.The BRFSS data set contains a variable called EdCollege, the proportion of adults who have completed college.(a) Plot the data with FruitVeg5 on the x axis and EdCollege on the y axis. Describe the overall pattern
CHALLENG E Eating fruits and vegetables and smoking. The Centers for Disease Prevention and Control (CDC) Behavioral Risk Factor Surveillance System (BRFSS) collects data related to health conditions and risk behaviors.53 Aggregated data by state are in the BRFSS data set described in the Data
Graduation rates. One of the factors used to evaluate undergraduate programs is the proportion of incoming students who graduate.This quantity, called the graduation rate, can be predicted by other variables such as the SAT or ACT scores and the high school record of the incoming students. One of
Self-esteem and work performance. People who do well tend to feel good about themselves. Perhaps helping people feel good about themselves will help them do better in their jobs and in life. Raising selfesteem became for a time a goal in many schools and companies. Can you think of explanations for
Exercise and mortalty. A sign in a fitness center says, “Mortality is halved for men over 65 who walk at least 2 miles a day.”(a) Mortality is eventually 100% for everyone.What do you think “mortality is halved” means?(b) Assuming that the claim is true, explain why this fact does not show
Artificial sweeteners. People who use artificial sweeteners in place of sugar tend to be heavier than people who use sugar. Does this mean that artificial sweeteners cause weight gain? Give a more plausible explanation for this association.
Watching TV and low grades. Children who watch many hours of television get lower grades in school on the average than those who watch less TV. Explain clearly why this fact does not show that watching TV causes poor grades. In particular, suggest some other variables that may be confounded with
Hospital size and length of stay. A study shows that there is a positive correlation between the size of a hospital (measured by its number of beds x)and the median number of days y that patients remain in the hospital. Does this mean that you can shorten a hospital stay by choosing a small
Computer chip manufacturing and miscarriages.A study showed that women who work in the production of computer chips have abnormally high numbers of miscarriages. The union claimed that exposure to chemicals used in production caused the miscarriages. Another possible explanation is that these
Coaching for the SAT. A study finds that high school students who take the SAT, enroll in an SAT coaching course, and then take the SAT a second time raise their SAT Mathematics scores from a mean of 521 to a mean of 561.51 What factors other than “taking the course causes higher scores”might
Music and academic performance. The Kalamazoo (Michigan) Symphony once advertised a “Mozart for Minors” program with this statement:“Question: Which students scored 51 points higher in verbal skills and 39 points higher in math?Answer: Students who had experience in music.”50 In fact, good
CHALL ENGE Health and income. An article entitled“The Health and Wealth of Nations” says:“The positive correlation between health and income per capita is one of the best-known relations in international development. This correlation is commonly thought to reflect a causal link running from
Exercise and self-confidence. A college fitness center offers an exercise program for staff members who choose to participate. The program assesses each participant’s fitness, using a treadmill test, and also administers a personality questionnaire. There is a moderately strong positive
CEO compensation and layoffs. “Based on an examination of twenty-two companies that announced large layoffs during 1994, Downs found a strong (.31) correlation between the size of the layoffs and the compensation of the CEOs.”48 This correlation is probably explained by common response to a
Marriage and income. Data show that men who are married, and also divorced or widowed men, earn quite a bit more than men who have never been married. This does not mean that a man can raise his income by getting married.Suggest several lurking variables that you think are confounded with marital
Online courses. Many colleges offer online versions of some courses that are also taught in the classroom. It often happens that the students who enroll in the online version do better than the classroom students on the course exams.This does not show that online instruction is more effective than
Treatment for cocaine addiction. Cocaine addiction can be difficult to overcome. Since addicts derive pleasure from the drug, one proposed aid is to provide an antidepressant drug. A 3-year study with 72 chronic cocaine users compared an antidepressant drug called desipramine with lithium and a
Career plans of young women and men. A study of the career plans of young women and men sent questionnaires to all 722 members of the senior class in the College of Business Administration at the University of Illinois. One question asked which major within the business program the student had
Survey response rates. A market research firm conducted a survey of companies in its state. They mailed a questionnaire to 300 small companies, 300 medium-sized companies, and 300 large companies. The rate of nonresponse is important in deciding how reliable survey results are. Here are the data on
Construct a table with no association. Construct a 3 × 3 table of counts where there is no apparent association between the row and column variables.
Complete the table. Here are the row and column totals for a two-way table with two rows and two columns:a b 200 c d 200 200 200 400 Find two different sets of countsa, b,c, and d for the body of the table that give these same totals. This shows that the relationship between two variables cannot be
Condition on gender. Refer to the previous two exercises. Find the conditional distribution of status for each gender. Describe the distributions graphically and write a short summary comparing the major features of these distributions.
Condition on status. Refer to the previous exercise. Find the conditional distribution of gender for each status. Describe the distributions graphically and write a short summary comparing the major features of these distributions.
Enrollment of recent high school graduates. The table below gives some census data concerning the enrollment status of recent high school graduates aged 16 to 24 years.40 The table entries are in thousands of students.Enrollment and gender Status Men Women Two-year college, full-time 890 969
Condition on status. Refer to the previous two exercises. Compute the conditional distribution of age for each of the two status categories. Display the distributions graphically and write a short paragraph describing the distributions and how they differ.
Condition on age. Refer to the previous exercise.Find the conditional distribution of status for each of the four age categories. Display the distributions graphically and summarize their differences and similarities.
Full-time and part-time college students. The Census Bureau provides estimates of numbers of people in the United States classified in various ways.39 Let’s look at college students. The following table gives us data to examine the relation between age and full-time or part-time status. The
A conditional distribution. Perform the calculations to show that the conditional distribution of binge drinking for men is Conditional distribution of binge drinking for men Yes No Percent 22.7% 77.3%
Find the percent. Show that the percent of men who are frequent binge drinkers is 22.7%.
Explain the marginal distribution. Explain how the marginal distribution of frequent binge drinking given in Example 2.31 is computed from the entries in the table given in Example 2.28.
Explain the computation. Explain how the entry for the women who are not binge drinkers in Example 2.29 is computed from the table in Example 2.28.
Read the margins of the table. How many women are subjects in the binge-drinking study? What is the total number of students who are not binge drinkers?
Read the table. How many female students are binge drinkers? How many are not?
Dangers of not looking at a plot. Table 2.6 presents four sets of data prepared by the statistician Frank Anscombe to illustrate the dangers of calculating without first plotting the data.35(a) Without making scatterplots, find the correlation and the least-squares regression line for all four data
Education and income. There is a strong positive correlation between years of education and income for economists employed by business firms. (In particular, economists with doctorates earn more than economists with only a bachelor’s degree.)There is also a strong positive correlation between
APPLET Use the applet. Go to the Correlation and Regression applet. Click on the scatterplot to create a group of 10 points in the lower-left corner of the scatterplot with a strong straight-line pattern (correlation about −0.9). In Exercise 2.46 you started here to see that correlation r is not
APPLET CAUTION! Use the applet. It isn’t easy to guess the position of the least-squares line by eye. Use the Correlation and Regression applet to compare a line you draw with the least-squares line. Click on the scatterplot to create a group of 15 to 20 points from lower left to upper right with
Stride rate and running speed. Exercise 2.98 gives data on the mean stride rate of a group of 21 elite female runners at various running speeds.Find the correlation between speed and stride rate.Would you expect this correlation to increase or decrease if we had data on the individual stride rates
City and highway gas mileage. Continue your work in Exercise 2.97. Find the regression line for predicting highway mileage from city mileage for the 20 two-seater cars other than the Honda Insight. Draw both regression lines on your scatterplot. Is the Insight very influential for the least-squares
Stride rate of runners. Runners are concerned about their form when racing. One measure of form is the stride rate, the number of steps taken per second. As running speed increases, the stride rate should also increase. In a study of 21 of the best American female runners, researchers measured the
City and highway gas mileage. Table 1.10 (page 31) gives the city and highway gas mileages for 21 two-seater cars, including the Honda Insight gas-electric hybrid car. In Exercise 2.45 you investigated the influence of the Insight on the correlation between city and highway mileage.(a) Make a
Climate change. Drilling down beneath a lake in Alaska yields chemical evidence of past changes in climate. Biological silicon, left by the skeletons of single-celled creatures called diatoms, measures the abundance of life in the lake. A rather complex variable based on the ratio of certain
Golf scores. The following table presents the golf scores of 11 members of a women’s golf team in two rounds of tournament play.Player 1 2 3 4 5 6 7 8 9 10 11 Round 1 89 90 87 95 86 81 105 83 88 91 79 Round 2 94 85 89 89 81 76 89 87 91 88 80 (a) Plot the data with the Round 1 scores on the x axis
Gas chromatography. Gas chromatography is a technique used to detect very small amounts of a substance, for example, a contaminant in drinking water. Laboratories use regression to calibrate such techniques. The data below show the results of five measurements for each of four amounts of the
Basal metabolic rate. Careful statistical studies often include examination of potential lurking variables. This was true of the study of the effect of nonexercise activity (NEA) on fat gain(Example 2.12, page 109), our lead example in Section 2.3. Overeating may lead our bodies to spontaneously
CHALLENGE Another example. Here is another example of the group effect cautioned about in the previous exercise. Explain how as a nation’s population grows older mean income can go down for workers in each age group, yet still go up for all workers.
CHALLENGE CAUTION! A lurking variable. The effect of a lurking variable can be surprising when individuals are divided into groups. In recent years, the mean SAT score of all high school seniors has increased. But the mean SAT score has decreased for students at each level of high school grades (A,
A test for job applicants. Your company gives a test of cognitive ability to job applicants before deciding whom to hire. Your boss has asked you to use company records to see if this test really helps predict the performance ratings of employees.Explain carefully to your boss why the
Effect of using means. Your plot for Exercise 2.87 shows that the increase of the mean weight of children in Nahya is very linear during the first 5 months of life. The correlation of age and weight is r = 0.9964 for the first 5 months. Weight in these data is the mean for 170 children. Explain why
Pesticide in olive oil. Exercise 2.80 gives data on the concentration of the pesticide fenthion in Greek olive oil that has been stored for various lengths of time. The exponential decay model used to describe how concentration decreases over time proposes a curved relationship between storage time
Growth of infants in Egypt. A study of nutrition in developing countries collected data from the Egyptian village of Nahya. Here are the mean weights (in kilograms) for 170 infants in Nahya who were weighed each month during their first year of life:31 Age (months) 1 2 3 4 5 6 7 8 9 10 11 12 Weight

Showing 2000 - 2100 of 6020

First
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Last

Step by Step Answers

Services

Sitemap
Fun
Definitions
Become Tutor
Used Textbooks
Study Help Categories
Recent Questions
Expert Questions
Campus Wear
Sell Your Books

Company Info

Security
Copyrights
Privacy Policy
Terms & Conditions
SolutionInn Fee
Scholarship
Online Quiz
Give Feedback, Get Rewards

Get In Touch

About Us
Contact Us
Career
Jobs
FAQ
Student Discount
Campus Ambassador

Secure Payment

Download Our App

© 2026 SolutionInn. All Rights Reserved