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
statistical techniques in business
Statistical Methods For The Social Sciences 5th Edition Alan Agresti - Solutions
Statistical interaction refers to which of the following?(a) Association exists between two variables.(b) The effect of an explanatory variable on a response variable changes greatly over the levels of a control variable.(c) The partial association is the same at each level of the control variable,
For all court trials about homicides in Florida in a certain period, the difference between the proportions of whites and blacks receiving the death penalty was 0.026 when the victim was black and −0.077 when the victim was white.10 This shows evidence of (a) a spurious association,(b)
For recent U.S. presidential elections, in each state wealthier voters tend to be more likely to vote Republican, yet states that are wealthier in an aggregate sense are more likely to have more Democrat than Republican votes (Gelman and Hill 2007, Section 14.2). Sketch a plot that illustrates how
A study9 reported a correlation of 0.68 between scores on an index of depression and scores on an index that measures the amount of saturated fat intake. True or false:You can conclude that if you increase your saturated fat intake by a standard deviation, your degree of depression will increase by
Exercise 7.17 on page 207 mentioned a study of compulsive buying behavior that conducted a national telephone survey. The study found that lower-income subjects were more likely to be compulsive buyers. They reported,“Compulsive buyers did not differ significantly from other respondents in mean
Give an example of three variables for which the effect of x1 on y would be(a) Spurious, disappearing when x2 is controlled.(b) Part of a chain relationship, disappearing when a mediator variable x2 is controlled.(c) Weakened, but not eliminated, when x2 is controlled.(d) Unaffected by controlling
A study of the relationship between student’s high school GPA and mother’s employment (yes, no) suspects an interaction with the gender of a student. Controlling gender, Table 10.10 shows results.(a) Describe the relationship between mother’s employment and GPA for females and for males. Does
The crude death rate is the number of deaths in a year, per size of the population, multiplied by 1000. According to the U.S. Bureau of the Census, recently Mexico had a crude death rate of 4.6 (i.e., 4.6 deaths per 1000 population) while the United States had a crude death rate of 8.4. Could the
The percentage of women who get breast cancer is higher now than a century ago. Suppose that cancer incidence tends to increase with age, and suppose that women tend to live longer now than a century ago. How might a comparison of breast cancer rates now with 100 years ago show different results
A research study funded by Wobegon Springs Mineral Water, Inc., discovers that the probability that a newborn child has a birth defect is lower for families that regularly buy bottled water than for families that do not.Does this association reflect a causal link between drinking bottled water and
A study observes that subjects who say they exercise regularly reported only half as many serious illnesses per year, on the average, as those who say they do not exercise regularly. The results section in the article states,“We next analyzed whether age was a confounding variable affecting this
Example 7.1 (page 182) discussed a study that found that prayer did not reduce the incidence of complications for coronary surgery patients.(a) Just as association does not imply causality, so does a lack of association not imply a lack of causality, because there may be an alternative explanation.
Eighth-grade math scores on the National Assessment of Educational Progress had means of 277 in Nebraska and 271 in New Jersey. For white students, the means were 281 in Nebraska and 283 in New Jersey. For black students, the means were 236 in Nebraska and 242 in New Jersey. For other nonwhite
Table 10.9 shows the mean number of children in Canadian families, classified by whether the family was English speaking or French speaking and by whether the family lived in Quebec or in another province. Let y =number of children in family, x1 = primary language of family, and x2 = province
Suppose that x1 = father’s education is positively associated with y = son’s income at age 40. However, for the regression analysis conducted separately at fixed levels of x2 = son’s education, the correlation does not differ significantly from zero. Do you think this is more likely to
Using the most recent General Social Survey, construct a contingency table relating gender (GSS variable SEX) and party identification (PARTYID). Is there still a gender gap? Control for political ideology (the GSS variable POLVIEWS) by forming partial tables for the most conservative and the most
For the Students data (Exercise 1.11), are there any pairs of variables for which you expect the association to disappear under control for a third variable? Explain.
Refer to the Students data file (Exercise 1.11 on page 9). Construct partial tables relating opinion about abortion to opinion about life after death, controlling for attendance at religious services, measured using the two categories (Never or occasionally, Most weeks or every week). Prepare a
A study of students at Oregon State University found an association between frequency of church attendance and favorability toward the legalization of marijuana.Both variables were measured in ordered categories.Controlling for gender, the gamma measures for the two partial tables were Males:
A study of the association between whether a smoker (yes, no) and whether have had some form of cancer (yes, no) has odds ratio 1.1 for subjects of age less than 30, 2.4 for subjects of age 30 to 50, and 4.3 for subjects of age over 50.(a) Identify the response variable, explanatory variable, and
For lower-level managerial employees of a fastfood chain, the prediction equation relating y = annual income (thousands of dollars) to x1 = number of years of experience on the job is ˆy = 14.2 + 1.1x1 for males andˆy = 14.2+0.8x1 for females. Explain how these equations show evidence of
According to the U.S. Census Bureau, in 2013 the population median income was estimated to be $29,127 for white females, $26,006 for black females, $41,086 for white males, and $30,394 for black males. Compare the difference in median incomes between males and females for (a) white subjects, (b)
When we analyze data for the census tracts in the greater Los Angeles area, we find no significant correlation between median tax bill and median lot size. Yet a considerable positive correlation occurs when we control for the percentage of the tract used for business. Explain how the percentage of
Table 10.8 relates y = exam score (1 = below median, 2 = above median) to gender, controlling for the subject of the exam (Math, Verbal). Show that subject of exam is a suppressor variable.
Table 10.7 lists the mean salary, in thousands of dollars, of faculty on nine-month contracts in U.S. institutions of higher education in 2013–2014, by gender and academic rank.(a) Suppose that gender is the explanatory variable. Identify the response variable and the control variable.(b)
Opposition to the legal availability of abortion is stronger among the very religious than the nonreligious, and it is also stronger among those with conservative sexual attitudes than those with more permissive attitudes. Draw a three-variable diagram of how these variables might be related,
For the Florida data file (shown partly on page 283), giving countywide data in Florida for several variables, a moderate positive correlation (r = 0.47) exists between crime rate and the percentage who are high school graduates. The percentage living in urban areas is also strongly correlated with
For the data on house sales shown partly in Table 9.5 on page 268, the number of bedrooms has a moderately strong positive correlation with selling price.Controlling for size of home, however, this association diminishes greatly.(a) Explain how this could happen, illustrating with a diagram showing
Table 10.6 relates occupational level (white collar, blue collar) and political party choice, controlling for income.(a) Construct the bivariate table between occupational level and political party, ignoring income. Is there an association? If so, describe it.(b) Do the partial tables display an
A study at your university finds that of those who applied to its graduate school last year, the percentage admitted was higher for the male applicants than for the female applicants. However, for each department that received applications, the percentage admitted was lower for the male applicants
Suppose race is related to frequency of juvenile arrests, with black juveniles more likely to be arrested than white juveniles. A possible chain relationship explanation is that (1) race affects family income, with blacks tending to have lower family incomes than whites, and(2) being poor increases
A study found that children who eat breakfast get better math grades than those who do not eat breakfast.This result was based on the association between x =whether eat breakfast (yes, no) and y = grade in last math course taken. How might this result be spurious, and how could you check for that
An Associated Press story quoted a study at the University of California at San Diego that reported, based on a nationwide survey, that those who averaged at least 8 hours of sleep a night were 12 percent more likely to die within six years than those who averaged 6.5 to 7.5 hours of sleep a
Figure 9.16 on page 274 showed a negative correlation between birth rate and television ownership. Identify a variable to help explain how this association could be spurious.
Explain what is meant by a spurious association, drawing a scatter diagram to illustrate.(a) Illustrate using x1 = shoe size, x2 = age, and y = number of books one has ever read, for children from schools in Winnipeg, Canada.(b) Illustrate using x1 = height, x2 = gender, and y =annual income, for a
Explain what it means to control for a variable, using an example to illustrate.
An association exists between college GPA and whether a college student has ever used marijuana.Explain how(a) The direction of a causal arrow might go in either direction.(b) A third variable might be responsible for the association.
Cities in the United States have a positive correlation between y = crime rate and x = size of police force.Does this imply that x causes y? Explain.
For all fires in Chicago last year, data are available on x = number of firefighters at the fire and y = cost of damages due to the fire. The correlation is positive.(a) Does this mean that having more firefighters at a fire causes the damage to be worse? Explain.(b) Identify a third variable that
A young child wonders what causes women to have babies. For each woman who lives on her block, she observes whether her hair is gray and whether she has young children. The four women with gray hair do not have young children, whereas all five women not having gray hair have young children.
State the three criteria for a causal relationship. For each, describe a relationship between two variables that is not causal because that criterion would be violated.
9.68.* From the formulas for b (page 252) and r (page 260), show that r = bsx/sy.
9.66.* Refer to the formula a = ¯y−b¯x for the y-intercept.(a) Show that substituting x = ¯x into the prediction equation ˆy = a + bx yields the predicted y-value of ˆy = ¯y.Show that this means that the least squares prediction equation passes through the point with coordinates ( ¯x,
9.64.* A confidence interval for a population correlationρ requires a transformation of r, T = (1/2) loge[(1 +r)/(1 − r)], for which the sampling distribution is approximately normal, with standard error 1/√n − 3. Once we get the endpoints of the interval for the population value of T, we
9.63.* Observations on both x and y are standardized, having estimated means of 0 and standard deviations of 1 (see Section 4.3). Show that the prediction equation has the form ˆy = rx, where r is the sample correlation between x and y. That is, for the standardized variables, the y-intercept
9.62.* A study by the National Highway Traffic Safety Administration estimated that 73% of people wear seat belts, that failure to wear seat belts led to 9200 deaths in the previous year, and that that value would decrease by 270 for every 1 percentage point gain in seat belt usage.Let ˆy =
The slope of the least squares prediction equation and the correlation are similar in the sense that(a) They do not depend on the units of measurement.(b) They both must fall between −1 and +1.(c) They both have the same sign.(d) They both equal 1 when there is the strongest association.(e) Their
The correlation is inappropriate as a measure of association between two quantitative variables(a) When different people measure the variables using different units.(b) When the relationship is highly nonlinear.(c) When the data points fall exactly on a straight line.(d) When the slope of the
One can interpret r = 0.30 as follows:(a) A30% reduction in error occurs in using x to predict y.(b) A 9% reduction in error occurs in using x to predict y compared to using ¯y to predict y.(c) 9% of the time ˆy = y.(d) y changes 0.30 units for every one-unit increase in x.(e) When x predicts y,
The variables y = annual income (thousands of dollars), x1 = number of years of education, and x2 =number of years of experience in job are measured for all the employees having city-funded jobs, in Knoxville, Tennessee. The following prediction equations and correlations apply:i. ˆy = 10 + 1.0x1,
Estimating a single mean μ corresponds to estimating the parameter in the simple model, E(y) = μ. Use this fact to explain why the estimate sy of the standard deviation of the marginal distribution has df = n − 1.
Explain carefully the interpretations of the standard deviations (a) sy, (b) sx, (c) s =square root of residualMS,(d) se for b.
Explain why the correlation between x = number of years of education and y = annual income is likely to be smaller if we use a random sample of adults who have a college degree than if we use a random sample of all adults.
For which student body do you think the correlation between high school GPAand college GPAwould be higher: Yale University or the University of Bridgeport, Connecticut? Explain why.
Refer to Exercise 9.39.For these counties, the correlation between high school education rate and median income equals 0.79.Suppose we also have data at the individual level as well as aggregated for a county. Sketch a scatterplot to show that at the individual level, the correlation could be much
A study by the Readership Institute10 at Northwestern University used survey data to analyze how reader behavior was influenced by the Iraq war. The response variable was a Reader Behavior Score (RBS), a combined measure summarizing newspaper use frequency, time spent with the newspaper, and how
For a class of 100 students, the teacher takes the 10 students who perform poorest on the midterm exam and enrolls them in a special tutoring program. The overall class mean is 70 on both the midterm and final, but the mean for the specially tutored students increases from 50 to 60. Use the concept
State the assumptions in fitting and making inferences with the model E(y) = α + βx.Which assumptions are most critical? In view of these assumptions, indicate why the model might not be adequate for(a) x = income, y = charitable contributions within the previous year. (Hint: Would poor people
A magazine article9 reported results of a study suggesting that “each extra year of schooling makes someone 10% less likely to describe himself as religious.” Explain how the 10% could be a slope estimate from a regression analysis, but the prediction equation obtained would apply over a
Annual income, in dollars, is an explanatory variable in a regression analysis. For a British version of the report on the analysis, all responses are converted to British pounds sterling (1 pound equals about 1.33 dollars, as of 2016).(a) How, if at all, does the slope of the prediction equation
For counties in a particular state, crime rate (number of crimes per thousand residents) in the past two years varies around a mean = 50 with standard deviation = 20.The crime rate last year has correlation 0.50 with the crime rate this year. Last year, the crime rate was 100 for the county having
Explain why conditional variability can be much less than marginal variability, using the relationship between y = weight and x = age for a sample of boys of ages 2–12, for which perhaps σy = 30 but the conditional σ = 10.
A recent Census Bureau survey reported that the mean total earnings that a full-time worker in the United States can expect to earn between ages 25 and 64 is $1.2 million for those with only a high school education and$2.1 million for those with a college degree but no advanced degree.(a) Assuming
The headline of an article in the Gainesville Sun newspaper stated, “Height can yield a taller paycheck.”It described an analysis of four large studies in the United States and Britain by a University of Florida professor on subjects’ height and salaries. The article reported that for each
A study,8 after pointing out that diets high in fats and sugars (bad for our health) are more affordable than diets high in fruit and vegetables (good for our health), reported, “Every extra 100 g of fats and sweets eaten decreased diet costs by 0.05 to 0.4 Euros, whereas every extra 100 g of
Refer to the UN data for several nations shown in Table 3.9 (page 53) and given at the text website. Using software, obtain the correlation matrix. Which pairs of variables are highly correlated? Describe the nature of those correlations, and inspect scatterplots to analyze whether any of them may
Refer to Table 9.1 (page 248), available in the Crime2 data file at the text website. Pose a research question about the relationship between the murder rate and the percentage of single-parent families. Using software, conduct analyses to address this question. Write a report showing your analyses
Table 9.15 shows a small excerpt of the Florida data file at the text website. That file has data from all 67 Florida counties on crime rate (number of crimes per 1000 residents), median income (in thousands of dollars), percentage of residents with at least a high school education(of those aged at
The Guns suicide data file at the text website shows statewide data7 on y = suicides (per 100,000 people)and x = percentage of residents who own a firearm.Conduct a regression and correlation analysis to analyze the association.
Refer to the UN data file shown in Table 3.9 on page 53. Pose a research question relating to the association between fertility and the gender inequality index.Using software, analyze data in that file to address this question, and summarize your analyses.
Pose a research question about job satisfaction and educational attainment. Using the most recent GSS data on SATJOB and EDUC with the multiple regression option at sda.berkeley.edu/GSS, with scores (1, 2, 3, 4) for (very satisfied, . . . , very dissatisfied), conduct a descriptive and inferential
Refer to the data file you created in Exercise 1.12.For variables chosen by your instructor, pose a research question and conduct a regression and correlation analysis.Report both descriptive and inferential statistical analyses, interpreting and summarizing your findings.
For the Students data file (Exercise 1.11 on page 9), conduct regression analyses relating (i) y = political ideology and x = religiosity, (ii) y = high school GPA and x = hours of TV watching. Prepare a report(a) Using graphical ways of portraying the individual variables and their
For the OECD data file for OECD nations in Table 3.13 on page 58, use software to construct a scatterplot relating x = carbon dioxide emissions and y = prison population.(a) Based on this plot, identify a point that has a large influence in determining the correlation. Show how the correlation
Refer to the previous exercise. When we regress political ideology in 2014 on x = number of hours spent in the home on religious activity in the past month(RELHRS1), we obtain------------------------------------------------B Std. Error Beta t Sig.Constant 4.0115 0.0422 95.10 0.0000 RELHRS1 0.0064
Is political ideology associated with income? When GSS data for 1478 cases in 2014 were used to regress y =political views (POLVIEWS, using scores 1–7 with 1 = extremely liberal and 7 = extremely conservative) on x =respondent’s income (RINCOME, using scores 1–12 for the 12 income
A study was conducted using 49 Catholic female undergraduates at Texas A&M University. The variables measured refer to the parents of these students. The response variable is the number of children that the parents have. One of the explanatory variables is the mother’s educational level, measured
For 2271 observations from the 2014 GSS on y =number of years of education (EDUC) and x = number of years of mother’s education (MAEDUC), ˆy =9.86 + 0.345x, with se = 0.0147 for the slope.(a) Test the null hypothesis that these variables are independent, and interpret.(b) Find a 95% confidence
Refer to the previous exercise. Now let the human development index (HDI) be the explanatory variable for predicting fertility. Using software with the UN data file at the text website,(a) Construct a scatterplot.Doany observations stand out as potential regression outliers?(b) Fit the model, and
Refer to Table 3.9 on page 53. This exercise uses y =fertility rate and x = gender inequality index. Table 9.13 shows part of an SPSS output for a regression analysis.(a) State a research question that could be addressed with this printout.(b) Report the prediction equation, and interpret.(c)
Refer to the Florida data file at the text website, shown partly in Table 9.15 for Exercise 9.39, giving countywide data for several variables in Florida. For those data, use software to analyze y = crime rate and x = percentage living in an urban environment.(a) Construct a box plot for y.
Refer to Table 9.1 and the Crime2 data file at the text website. For all 51 observations, use software to analyze the relationship between y = murder rate and x =poverty rate.(a) Construct a scatterplot. Does there seem to be a positive, or a negative, relationship?(b) Report the prediction
For the Houses data file (shown partly in Table 9.5), Table 9.12 shows a regression analysis relating selling price to number of bedrooms.(a) Report the prediction equation, and interpret the slope.(b) Report r2, and interpret its value.(c) Report the correlation and its confidence interval, and
For data on several nations, we want to describe whether the percentage of people using the Internet is more strongly associated with per capita GDP or with the fertility rate.(a) Can we compare the slopes when GDP and fertility each predict Internet use in separate regression equations?Why or why
In the UN Human Development Report, one variable measured was x = percentage of adults who use contraceptive methods. Table 9.11 shows part of a regression analysis using y = fertility (mean number of children per adult woman), for 22 nations listed in that report. For those nations, x had a mean
For 2014 GSS data, the correlation matrix for subject’s education (EDUC), mother’s education (MAEDUC), and father’s education (PAEDUC) is EDUC PAEDUC MAEDUC EDUC 1.00 .46 .45 PAEDUC .46 1.00 .69 MAEDUC .45 .69 1.00 Interpret this matrix, identifying the pair of variables with the strongest
Access the Houses data file (shown partly in Table 9.5) at the text website. For the response variable taxes and explanatory variable size, using software,(a) Graphically portray the association, and describe it.(b) Find and interpret the prediction equation.(c) Find and interpret the correlation
The prediction equation relating x = years of education and y = annual income (in dollars) is ˆy = −20,000+4000x, and the correlation equals 0.50.The standard deviations were 2.0 for x and 16,000 for y.(a) Show how to find the correlation from the slope.(b) Results were translated to units of
For students who take Statistics 101 at Lake Wobegon College in Minnesota, both x = midterm exam score and y = final exam score have mean = 75 and standard deviation = 10.(a) The prediction equation is ˆy = 30 + 0.60x. Find the predicted final exam score for a student who has(i) midterm score =
For the study in Example 9.6 (page 258) of y = high school GPA and x = weekly number of hours viewing television, ˆy = 3.44 − 0.03x.(a) The study reported that r-squared = 0.237.Interpret.(b) Report and interpret the correlation.(c) Suppose you found the correlation only for those students
For the student survey data set described in Exercise 1.11, the sample correlation between y = political ideology(scored 1 to 7, with higher values representing more conservatism) and x = number of times a week reading a newspaper is r = −0.066.(a) Would you conclude that the sample association
The Internet site www.artofstat.com/webapps.html has an Explore Linear Regression applet. To show the impact of an outlier, use the Draw Own option to put 10 points on the scatterplot that have a correlation close to +1, and then add a single point that changes the correlation to a negative value.
Table 9.15 in Exercise 9.39 shows countywide data for several variables in Florida. For those counties, Table 9.10 shows part of the output for the regression analysis relating y = median income (in thousands of dollars)to x = percentage of residents with at least a high school education.(a) Report
A report summarizing the results of a study on the relationship between a verbal aptitude test x and a mathematics aptitude test y states that ¯x = 480, ¯y = 500, sx =80, sy = 120, and r = 0.60.Using the formulas for the correlation and for the least squares estimates, find the prediction
Figure 9.20 is a scatterplot relating y =percentage of people using cell phones and x = per capita gross domestic product (GDP) for some nations listed in the Human Development Report.(a) Give the approximate x- and y-coordinates for the nation that has the highest (i) cell phone use, (ii) GDP.(b)
In the 2000 Presidential election in the United States, the Democratic candidate was Al Gore and theRepublican candidate was George W. Bush. In Palm Beach County, Florida, initial election returns reported 3407 votes for the Reform party candidate, Pat Buchanan.Some political analysts thought that
Access the data file Crime2 shown in Table 9.1.Let y = violent crime rate and x = poverty rate.(a) Using software, show that the prediction equation isˆy = 209.9+25.5x. Interpret the y-intercept and the slope.(b) Find the predicted violent crime rate and the residual for Massachusetts, which had x
For the 2014 GSS, a prediction equation relates y =highest year of school completed to x = father’s highest year of school completed.(a) Which equation is more realistic for the result: ˆy =9.57 + 0.35x, or ˆy = 0.35 + 9.57x?Why?(b) Suppose the prediction equation had been ˆy = x.Identify the
Access the UN data file (shown in Table 3.9) at the text website from 42 countries. Let y = carbon dioxide emissions (metric tons per capita) and x = gross domestic product (per capita GDP, in dollars).(a) Find the prediction equation, and interpret the coefficients.(b) For the United States, x =
The Firearms data file at the text website shows U.S. statewide data on x = percentage of people who report owning a gun and y = firearm death rate (annual number of deaths per 100,000 population), from www.cdc.gov.(a) Find the prediction equation, and interpret.(b) The correlation is 0.70.Identify
Showing 3300 - 3400
of 5757
First
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
Last
Step by Step Answers
Get 50% OFF
Claim Now
