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
S
Books
FREE
Study Help
Expert Questions
Accounting
General Management
Mathematics
Finance
Organizational Behaviour
Law
Physics
Operating System
Management Leadership
Sociology
Programming
Marketing
Database
Computer Network
Economics
Textbooks Solutions
Accounting
Managerial Accounting
Management Leadership
Cost Accounting
Statistics
Business Law
Corporate Finance
Finance
Economics
Auditing
Tutors
Online Tutors
Find a Tutor
Hire a Tutor
Become a Tutor
AI Tutor
AI Study Planner
NEW
Sell Books
Search
Search
Sign In
Register
study help
business
a course in statistics with r
Mind On Statistics 5th Edition Jessica M Utts, Robert F Heckard - Solutions
4.54 Refer to the Minitab output for Exercise 4.52.a. Demonstrate how the expected count was computed for the “age 18–29, yes” cell of the table.b. Verify that the expected count for the “301, yes” cell can be determined by subtracting the answer for part (a)from the total count for the
4.53 Refer to the Minitab output for Exercise 4.52. The first term of the sum for the chi-square statistic is 7.857 (corresponding to the “18–29, Yes” cell). Show how it was computed.
4.52 The table for Exercise 4.27 gave data for the relationship between age group and whether or not a person reports ever having seen a ghost.a. Write null and alternative hypotheses about the possible relationship between the two variables.b. The Minitab output for a chi-square test of the
4.51 Explain whether each of the following is possible.a. A relationship exists in the observed sample but not in the population from which the sample was drawn.b. A relationship does not exist in the observed sample but does exist in the population from which the sample was drawn.c. A relationship
4.50 If a relationship has practical significance, does it guarantee that statistical significance will be achieved in every study that examines it? Explain.
4.49 If a relationship is statistically significant, does that guarantee that it also has practical significance? Explain.
4.48 A sample of 90 men and 110 women is asked about their handedness. A two-way table of observed counts follows:Lefthanded Righthanded Total Men 11 79 90 Women 9 101 110 Total 20 180 200a. Calculate a table of expected counts for these data.b. Calculate the value of the chi-square statistic for
4.47 For each of the following results, explain what conclusion can be made about the null hypothesis that there is no relationship between two variables that form a 2 3 2 contingency table.a. p-value 5 .049.b. p-value 5 .755.c. p-value 5 .027d. Chi-square statistic 5 2.98.
4.46 For each of the following results, explain what conclusion can be made about the null hypothesis that there is no relationship between two variables that form a 2 3 2 contingency table.a. p-value 5 .001.b. p-value 5 .101.c. p-value 5 .900.d. Chi-square statistic 5 4.01.
4.45 In a national survey, n 5 1500 randomly selected adults are asked if they favor or oppose a ban on texting while driving and if they have personally texted while driving during the previous month. Write null and alternative hypotheses about the relationship between the two variables in this
4.44 Refer to Exercise 4.43.a. Calculate a table of expected counts for the data in Exercise 4.43.b. Show calculations verifying that the value of the chisquare statistic is 17.78.
4.43 The 2 3 2 contingency table that follows shows data for sex and opinion on the death penalty for respondents in the 2008 General Social Survey in which a random sample of adults in the United States was surveyed. (Raw data are in the GSS-08 dataset on the companion website.)Opinion on Death
4.42 In a national survey, n 1000 randomly selected adults are asked how important religion is in their own lives (very, fairly, or not very) and whether they approve or disapprove of same-sex marriage. Write null and alternative hypotheses about the relationship between the two variables in this
4.41 Refer to Exercise 4.40.a. Write a two-way table of observed counts for sex and whether a participant in soccer had a lower-extremity injury or not.b. Determine a two-way table of expected counts for these data.c. Show calculations verifying that the value of the chisquare statistic is 2.51.
4.40 Researchers studied a random sample of North Carolina high school students who participated in interscholastic athletics to learn about the risk of lower-extremity injuries(anywhere between hip and toe) for interscholastic athletes(Yang et al., 2005). Of 999 participants in girls’ soccer, 74
4.39 The success rates of two treatments (A and B) for clinical depression are being compared. The research team included five doctors, and the participants were 200 patients with depression. The doctors were supposed to randomly assign treatments to patients, but two doctors didn’t do this.
4.38 A researcher observes that, compared to students who do not procrastinate, students who admit to frequent procrastination are more likely to miss class due to illness. Does this mean that procrastinating increases illness? What is another explanation?
4.37 A well-known example of Simpson’s paradox, published by Bickel, Hammel, and O’Connell (1975), examined admission rates for men and women who had applied to graduate programs at the University of California at Berkeley. The actual data for specific programs is confidential, so we are using
4.36 Suppose two hospitals are willing to participate in an experiment to test a new treatment, and both hospitals agree to include 1100 patients in the study. Because the researchers who are conducting the experiment are on the staff of hos pital A, they decide to perform the majority of cases
4.35 In a 1997 Marist College Institute for Public Opinion survey of 995 randomly selected Americans, 31% of the men and 12% of the women surveyed said they have dozed off while driving (Source: www.mipo.marist.edu). Think of a third variable that might at least partially explain the observed
4.34 This exercise presents a real example of Simpson’s paradox(Wagner, 1982). The total income and total taxes paid in the United States in each of five income categories are given for 2 years, 1974 and 1978, in the following table:1974 1978 Adjusted Gross Income Income Tax Income Tax
4.33 Refer to Exercise 4.32, in which one or more third variables are at least partially likely to account for the observed relationship between religious activities and reduced incidence of high blood pressure. Is this an example of Simpson’s paradox?Explain.
4.32 Case Study 1.5 (p. 4) was called “Does Prayer Lower Blood Pressure?” One of the results quoted in that study was,“People who attended a religious service once a week and prayed or studied the Bible once a day were 40% less likely to have high blood pressure than those who don’t go to
4.31 The teacher of a class you’re taking tells the class that he thinks students who often skip classes have twice the risk of failing the class compared to students who regularly attend class. To better understand his claim, what question(s)would be reasonable to ask the professor?Section 4.3
4.30 Discuss how you might estimate your risk of being injured falling down stairs in the next year.
4.29 Suppose that you read in your hometown newspaper that there were 80 home burglaries in your town in the past year compared to only 65 in 1990. Explain why this might not mean that your home is more at risk for a burglary now than it was in 1990.
4.28 Suppose a newspaper article states that drinking three or more cups of coffee per day doubles the risk of gall bladder cancer. Before giving up coffee, what questions should be asked by a person who drinks this much coffee?
4.27 The Roper Organization (1992) conducted a study as part of a larger survey to ascertain the number of U.S. adults who had experienced phenomena such as seeing a ghost, “feeling as if you left your body,” and seeing a UFO. A representative sample of adults (18 and over) in the continental
4.26 Exercise 4.11 gave data on height and whether or not a student had ever been bullied for 209 secondary school students in England. Among 92 short students, 42 had been bullied. Among 117 students who were not short, 30 had been bullied.a. For each height category, calculate the risk of having
4.25 Exercise 4.10 described a study in which men were classified according to how many anger symptoms they exhibit and whether they have coronary heart disease or not. Among 559 men with the most anger symptoms, 59 had coronary heart disease. Among 199 men with no anger symptoms, 8 had coronary
4.24 Using the terminology of this chapter, what name applies to each of the boldface numbers in the following quotes (e.g., odds, risk, relative risk)?a. “Fontham found increased risks of lung cancer with increasing exposure to secondhand smoke, whether it took place at home, at work, or in a
4.23 The relative risk of contracting a certain coronary disease is 2.0 for male smokers compared to male nonsmokers and 3.0 for female smokers compared to female nonsmokers. Is this enough information to determine whether male smokers or female smokers are more likely to contract the disease? If
4.22 Science News (February 25, 1995, p. 124) reported a study of 232 people aged 55 or over who had had heart surgery. The patients were asked whether or not their religious beliefs give them feelings of strength and comfort and whether or not they regularly participate in social activities. Of
4.21a. For a relative risk of 1.53, what is the percent increase in risk?b. For a percent increase in risk of 140%, what is the relative risk?General Section Exercises
4.20a. For a relative risk of 2.1, what is the percent increase in risk?b. For a percent increase in risk of 40%, what is the relative risk?
4.19 If the baseline risk of a certain disease for nonsmokers is 1% and the relative risk of the disease is 5 for smokers compared to nonsmokers, what is the risk of the disease for smokers?
4.18 For nausea, compute each of the following.a. The risk of experiencing nausea for each drug(separately).b. The relative risk of nausea for Drug 1 compared to Drug 2.c. The percent increase in the risk of nausea for Drug 1 compared to Drug 2.d. The odds ratio for comparing the odds of nausea for
4.17 For the headache side effect, compute each of the following.a. The risk of experiencing a headache for each drug(separately).b. The relative risk of a headache for Drug 1 compared to Drug 2.c. The percent increase in the risk of a headache for Drug 1 compared to Drug 2.d. The odds ratio for
4.16 This is a modification of Exercise 1.4. The risk of getting lung cancer at some point in one’s life for men who have never smoked is about 13 in 1000. The risk for men who smoke is just over 13 times the risk for nonsmokers (Source:Villeneeve and Lau, 1994).a. Expressed as a percentage, what
4.15 For each of the following measures, give the value that implies no difference between the two groups being compared.a. Relative risk.b. Odds ratio.c. Percent increase in risk.
4.14 Anton and Edward often play a game together, so they decide to see whether or not who goes first affects who wins.They keep track of 50 games, with each going first 25 times.Of the 25 times Anton went first, he won 15 times. Of the 25 times Edward went first, he won 12 times. In constructing a
4.13 In a 1997 poll conducted by the Los Angeles Times, 1218 southern California residents were surveyed about their health and fitness habits. One of the questions was, “What is the most important reason why you try to take care of your body: Is it mostly because you want to be attractive to
4.12 In a class survey, statistics students at a university were asked, “Regarding your weight, do you think you are: About right? Overweight? Underweight?” The following table displays the results by sex:Sex and Perception of Weight Perception of Weight Sex About Right Overweight Underweight
4.11 In a study done in England, Voss and Mulligan (2000) collected data on height (short or not) and whether or not the student had ever been bullied in school for 209 secondary school students.A student was categorized as short if he or she was below the third percentile for height on school
4.10 Do grumpy old men have a greater risk of having coronary heart disease than men who aren’t so grumpy? Harvard Medical School researchers examined this question in a prospective observational study reported in the November 1994 issue of Circulation (Kawachi et al., 1994). For 7 years, the
4.9 Students in a class were asked whether they preferred an inclass or a take-home final exam and were then categorized as to whether or not they had received an A on the in-class midterm. Of the 25 A students, 10 preferred a take-home exam, while of the 50 non-A students, 30 preferred a takehome
4.8 In the 2008 General Social Survey, religious preference and opinion about when premarital sex might be wrong were among the measured variables. The contingency table of counts for these variables is as follows:Religious Preference and Opinion about Premarital Sex When Is Premarital Sex
4.7 Suppose a study on the relationship between gender and political party included 200 men and 200 women and found 180 Democrats and 220 Republicans. Is that information sufficient for you to construct a contingency table for the study? If so, construct the table. If not, explain why not.General
4.6 For each pair of variables, indicate whether or not a two-way table would be appropriate for summarizing the relationship.In each case, briefly explain why or why not.a. Age group (under 20, 21–29, etc.) and rating of a song on 1 to 5 scale (1 5 hate it, 5 5 love it).b. Gender and opinion
4.5 For each pair of variables, indicate whether or not a two-way table would be appropriate for summarizing the relationship.In each case, briefly explain why or why not.a. Political party (Republican, Democrat, etc.) and opinion about a new gun control law.b. Weight (pounds) and height (inches).
4.4 The following two-way table of counts summarizes data for age group and frequency of reading newspapers for respondents in the 2008 General Social Survey.Frequency of Reading Newspapers Age Group Every Day A Few Times a Week Once a Week Less Than Once a Week Total 18–29 45 68 38 83 234
4.3 Each fall, auditions for the band and orchestra are held at a large university. Last fall, the numbers of males and females in each class who auditioned were as follows:Class Female Male Total Freshman 170 100 270 Sophomore 50 50 100 Junior 60 20 80 Senior 20 30 50 Total 300 200 500a. Calculate
4.2 The following two-way table of counts summarizes whether respondents smoked or not and whether they had ever divorced or not for persons in the 1991–1993 General Social Surveys who had ever been married.Ever Divorced?Smoke? Yes No Total Yes 238 247 485 No 374 810 1184 Total 612 1057 1669 Data
4.1 The following table shows data for grades usually achieved in school and how often the respondent puts on sunscreen when going out in the sun for more than 1 hour. Respondents are 12th-grade participants in the 2003 Youth Risk Behavior Surveillance System survey. The survey, sponsored by the
3.100 Use the dataset temperature on the companion website. A portion of this dataset was presented in Exercise 3.9, in which the relationship between mean August temperature and geographic latitude was analyzed. For predicting mean April temperature (AprTemp), which of these two variables in the
3.99 Use the dataset UCDwomht on the companion website. For a sample of college women, the variable height is student’s height (in inches), and the variable midparent is the average height of the student’s parents (in inches) as reported by the student.a. Compute the regression equation for
3.98 In 1993, Forbes Magazine identified what it considered to be America’s 60 best small companies, and published the ages and salaries of their CEOs. The data are in the dataset ceodata on the companion website. The annual salaries (in thousands of dollars) for 59 of these CEOs are in the
3.97 Use the dataset idealwtmen on the companion website. It contains data for the men used for Case Study 3.1. The variable diff is the difference between actual and ideal weights and was computed as diff 5 actual 2 ideal.a. Plot diff (y) versus actual (x, actual weight). Does the relationship
3.96 The dataset bodytemp on the companion website includes sex, age, and body temperature for 100 blood donors who ranged in age from 17 to 84.a. Create a scatter plot of body temperature (y) and age (x)using different symbols for men and women. Is there an obvious difference in the relationship
3.95 Use the sats98 dataset on the companion website.a. Plot the relationship between average verbal (Verbal)and average math (Math) SAT scores in the 50 states.Describe the characteristics of the relationship.b. What states are outliers? In what specific way are they outliers?
3.94 Use the dataset sats98 on the companion website for this exercise. The variable Verbal contains the average scores on the verbal SAT in 1998 for the 50 states and the District of Columbia. PctTook is the percent of high school graduates, in each state, who took the SAT that year.a. Make a
3.93 Use the dataset cholesterol on the companion website. For n 5 28 heart attack patients, the variables 2-Day and 4-Day are cholesterol levels measured 2 days and 4 days, respectively, after the attacks.a. Plot 4-Day (y) versus 2-Day (x). Describe the direction and strength of the relationship,
3.92 Use the dataset oldfaithful on the companion website; it gives data for n 5 299 eruptions of the Old Faithful geyser.The variable Duration is the duration (minutes) of an eruption, and the variable TimeNext is the time interval (minutes)until the next eruption.a. Plot TimeNext (y) versus
3.91 Use the dataset poverty on the companion website; it includes teenage mother birth rates and poverty rates for the 50 states and the District of Columbia. The variable PovPct is the percent of a state’s population in 2000 living in households with incomes below the federally defined poverty
3.90 Use the dataset ceodata08 on the companion website for this exercise, which gives the ages (Age) and salaries(Salary) for the 50 highest-paid CEOs on the Fortune 500 list of top companies in the United States (Data source:http://www.forbes.com/lists/2009/12/best-boss-09_
3.89 The following is from Thought Question 3.4 on page 89.Sometimes the main purpose of a regression analysis is to determine the nature of the relationship between two variables, and sometimes the main purpose is to use the equation in the future to predict a y value when the x value is known.
3.88 Measure the heights and weights of ten friends of the same sex.a. Draw a scatterplot of the data, with weight on the vertical axis and height on the horizontal axis. Draw a line onto the scatterplot that you believe describes the average pattern. On the basis of two points on this line,
3.87 Give an example of a situation not mentioned elsewhere in this chapter in which two variables have no causal connection but are highly correlated because they are both related to a third variable. Explain what the third variable is.
3.86 For a statistics class project at a large northeastern university, a student examined the relationship between the following two variables:x 5 body weight (in pounds)y 5 time to chug a 12-ounce beverage (in seconds)We’ll leave it to you to imagine the beverage. The student collected data
2.58. What is the value of the prediction error for 2010?c. What is the slope of the line? Interpret the slope in the context of these variables.d. Based on the regression line, what would be the predicted persons per household in the year 2200? Realistically, what is the lowest possible value of
3.85 Refer to Exercise 3.84 about the trend in number of persons per household.a. Using statistical software, determine the least squares line for these data. Use the equation of this line to estimate the number of persons per household in the year 2010 (Data source: perhouse dataset on the
3.84 U.S. Census Bureau estimates of the average number of persons per household in the United States for census years between 1850 and 2000 are shown in the following table. (These data are in the file perhouse on the companion website.)Persons per Household in the United States Year Per Household
3.83 The following table (continued at the top of the next page) lists the number of pages and the price for 18 books, sorted in order of increasing number of pages. Ten of the books are hardcover and eight are softcover. (These data are in the dataset ProfBooks on the companion website.)a. Draw a
3.82 The winning time in the Olympic men’s 500-meter speed skating race over the years 1924 to 2006 can be described by the following regression equation:Winning time 5 272.63 2 0.1184 1Year2 Note: Beginning with the 1998 Olympics each competitor skated twice and the average of the two times
3.81 Refer to Exercise 3.80 about y 5 foot length and x 5 height. (Data source: the heightfoot dataset on the companion website.) If the person who reportedly is 84 inches tall is excluded, the regression equation for the remaining 32 men is y^ 5 0.25 1 0.384x.a. How much does average foot length
3.80 The heights (inches) and foot lengths (cm) of 33 college men are shown in the following table. (These data are in the dataset heightfoot on the companion website.)Height (in) and Foot Length (cm) for 33 College Students Student Height Foot Length 1 66.5 27.0 2 73.5 29.0 3 70.0 25.5 4 71.0 27.9
3.79 Refer to Case Study 3.1, in which regression equations are given for males and females relating ideal weight to actual weight. The equations are Women: Ideal 5 44 1 0.6 1Actual2 Men: Ideal 5 53 1 0.7 1Actual2a. Predict the ideal weight for a man who weighs 140 pounds and for a woman who weighs
3.78 The regression line relating verbal SAT scores and college GPA for the data exhibited in Figure 3.12 is Average GPA 5 0.539 1 0.00362 1Verbal SAT2a. Estimate the average GPA for those with verbal SAT scores of 600.b. Explain what the slope of 0.00362 represents in terms of the relationship
3.77 The regression relationship for y 5 student height and x 5 father’s height for the 10 female students listed in the table for Exercise 3.12 and in the dataset UCDchap3 is y^ 5 19.42 1 0.658xa. Give the value of the y-intercept. Does it have a meaningful interpretation in this situation?
3.76 Refer to Exercise 3.75 in which the regression relationship between age in years and body temperature in degrees Fahrenheit is given as y^ 5 98.6 2 0.0138x, based on data from 100 blood donors ranging in age from 17 to 84 years old.a. What is the y-intercept for this relationship? Does it have
3.75 The dataset bodytemp on the companion website gives age in years and body temperature in degrees Fahrenheit for 100 blood donors ranging in age from 17 to 84 years old. The regression equation is y^ 5 98.6 2 0.0138x.a. In the regression relationship shown, which variable is the response
3.74 Example 2.2 (p. 21) described an observational study in which it was found that children who slept with a nightlight or in a fully lit room before the age of 2 were more likely to be nearsighted than children who slept in darkness.Does this mean that sleeping with a light on as an infant
3.73 Researchers have shown that there is a positive correlation between average fat intake and the breast cancer rate across countries. In other words, countries with higher fat intake tend to have higher breast cancer rates. Does this correlation prove that dietary fat is a contributing cause of
3.72 It is said that a higher proportion of drivers of red cars are given tickets for traffic violations than drivers of any other car color. Does this mean that if you drive a red car rather than a car of some other color, it will cause you to get more tickets for traffic violations? Explain.
3.71 Give an example not given elsewhere in this chapter of two variables that are likely to be correlated because they are both changing over time.
3.70 Suppose a medical researcher finds a negative correlation between amount of weekly walking and the incidence of heart disease for people over 50 years old; in other words, people who walked more had a lower incidence of heart disease. One possible explanation for this observed association is
3.69 Give an example of a situation in which it would be reasonable to conclude that an explanatory variable causes changes in a response variable.
3.68 Suppose that in an observational study, it is observed that the risk of heart disease increases as the amount of dietary fat consumed increases. Write a paragraph discussing why this result does not necessarily imply that diets high in fat cause heart disease.
3.67 Suppose the indicated relationship has been found between each of the following sets of variables. For each set, specify the explanatory variable and the response variable. Then provide a possible reason for the relationship, other than the explanatory variable is causing a change in the
3.66 Suppose a positive relationship had been found between each of the following sets of variables. For each set, specify the explanatory variable and the response variable. Then provide a possible reason for the relationship, other than the explanatory variable is causing a change in the response
3.65 The pennstate2 dataset on the companion website includes heights and the total number of ear piercings for each person in a sample of college students. The correlation between the two variables is 20.495. What third variable may explain this observed correlation? Explain how that third
3.64 Based on the data for the past 50 years in the United States, there is a strong correlation between yearly beer sales and yearly per capita income. Would you interpret this to mean that increasing a person’s income will cause him or her to drink more beer? Explain.
3.63 Explain why a strong correlation would be found between weekly sales of firewood and weekly sales of cough drops over a 1-year period.
3.62 The table for Exercise 3.9 gave the average August temperature(y) and geographic latitude (x) for 20 cities in the United States. (The data are part of the temperature dataset on the companion website.) Exercise 3.18 gave the information that the regression equation relating these two
3.61 In Exercise 3.21, a regression equation relating x 5 putting distance (feet) to y 5 success rate (in percent) for professional golfers was given as Success rate 5 76.5 2 3.95 (Distance)The equation was based on observations of distances ranging from 5 feet to 15 feet.a. Use the equation to
3.60 The data in the following table come from a time when the United States had a maximum speed limit of 55 miles per hour in all states. An issue of some concern at that time was whether lower speed limits reduce the highway death rate.(These data are called speedlimit on the companion
3.59 Give an example of a prediction that is an extrapolation. Do not give an example that is already in this chapter.
3.58 The data in the table for Exercise 3.11 gave the square footage and asking price for nine homes for sale in Orange County, California in February 2010. The house with a square footage of 5500 is an obvious outlier. The value of r 2 for the relationship between y 5 asking price and x 5 square
3.57 A memorization test is given to ten women and ten men.The researchers find a negative correlation between scores on the test and height. Explain which of the reasons listed at the beginning of Section 3.4 for misleading correlations might explain this finding. Sketch a scatterplot for the
3.56 When a correlation value is reported in research journals, there often is not an accompanying scatterplot. Explain why reported correlation values should be supported with either a scatterplot or a description of the scatterplot.
Showing 1300 - 1400
of 2302
First
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Last
Step by Step Answers
Get 50% OFF
Claim Now
