Question: A random sample of 29 community college

> A used-car dealer is purchasing 50 used BMWs from one dealer in order to sell them for a profit. Working with collected data, the dealer has found a regression model to predict the selling price on the basis of the car’s age. He wants to predict the tota

> A student who has been accepted by two colleges wants to estimate what GPA he might get at the two colleges. His data consist of SAT scores and GPAs from random samples of recent graduates at each college. He wishes to predict his GPA at each school, usi

> In exercise 14.16 you examined the association between movie budgets and box office gross income. Would a 95% confidence interval for the slope, based on the same data, include 0? Explain.

> The output provided for exercise 14.20 provides a regression line to predict the amount of trash produced by a household on the basis of the number of people living in the household. Suppose you found a 95% confidence interval for the intercept of the re

> A regression analysis was conducted using data on success rates and retention rates in transfer courses at a sample of California community colleges. Assume the conditions for the linear model regression model are satisfied. a. Interpret the slope in con

> Figure A shows a scatterplot of the percent passing the bar exam within two years of graduation and the percent employed at graduation for U.S. law school graduates in 2015. Figure B shows the residual plot of the data. Evaluate the residual plot to dete

> Figure A shows a scatterplot of the price and age of a random sample of used Acura MDX cars and includes the regression line. Figure B shows a residual plot based on the regression line. (Source: cars.com) a. Is the regression model appropriate for these

> The table shows the number of floors and the height (in feet) of the five tallest buildings in Dubai. The regression model for predicting the height of a building from the number of floors is height = -558.45931 + 19.934126 Floors Complete the table by f

> The registrar at a small college says she can predict the number of units that a full-time student has accumulated on the basis of the number of semesters the student has attended the college by using the equation Predicted Units = 0 + 14 Semesters This

> A doctor says he can predict the height (in inches) of a child between 2 and 9 years old from the child’s age (in years) by using the equation Predicted Height = 31.78 + 2.45 Age This tells us the deterministic part of the regression model. What factors

> Figure A shows a scatterplot of some simulated data, and Figure B shows a residual plot of the same data. Is the linear regression model appropriate for these data? Why or why not? Assume the observations are independently measured.

> Figure A shows a scatterplot of wages of twins for a group of 183 pairs of twins. Figure B shows a residual plot of the same data. Figure C shows a QQ plot of these residuals. Is the linear regression model appropriate for these data? Why or why not? Ass

> Figure A shows a scatterplot of the number of print and electronic holdings for a sample of large U.S. libraries. Figure B shows a QQ plot of the residuals. Is the Normality condition of the linear regression model satisfied? Explain.

> Figure A shows a scatterplot of the current salary (in thousands of dollars per year) and the beginning salary for many employees at one company. Figure B shows a residual plot of the same data. Is linear regression appropriate for these data? Why or why

> A student wishes to buy a used car. He finds a consumer website that says the price of a used car is determined by its age according to the following formula: Predicted price in thousands of dollars = 17 - 0.8 (age in years) This is the deterministic com

> Figure A shows a scatterplot for the number of semesters that students have attended a community college and the number of credits they have accumulated. Figure B shows a residual plot of the same data. Is the linear regression model appropriate for thes

> In a 2016 study by ToptaÅŸ published in Academic Journals, a music educator conducted research to determine if students could successfully memorize a piano piece using only short periods of daily practice (ToptaÅŸ 2016). In addition

> Studies have shown that young adults experience faster weight gain and consume more unhealthy food than any other age group. In a 2017 study published in PLOS One, Buchanan et. al examined the effects of online marketing on young adultsâ€&#153

> Are students who participate in sports more extraverted than those who do not? A random sample of students at a small university were asked to indicate whether they participated in sports (yes or no) and to rate their level of extraversion. Extraverts ar

> We performed a randomization test to determine whether the mean number of days since an ethics professor contacted his or her mother is different from the mean number of days for a professor in a field other than ethics. The data consisted of a random sa

> Refer to exercise 13.35, which discussed a study on the effects of cloud seeding to produce rainfall. Some researchers think that cloud seeding has little effect on “low rain potential” clouds. Instead, they claim, mos

> Does soda constitute a larger part of the diet for women than it does for men? A StatCrunch survey asked people to report the percentage of their liquid intake that is soda. The sample mean for the 169 females was 19.51%, and the sample mean for the 163

> Find the difference in number of texts received and the number sent for females. Do the same for males. Then determine whether the differences are significantly different at the 0.05 level using the two-sample t-test.

> Determine whether the number of texts sent by males and the number received by males are significantly different at the 0.05 level using a paired t-test.

> Determine whether the number of texts sent by females and the number received by females are significantly different at the 0.05 level using a paired t-test.

> Determine whether the median number of texts sent and the median number received for all StatCrunch users are different at the 0.05 level by using a sign test.

> Determine whether the population mean number of texts sent and the population number received (for all the respondents) is different at the 0.05 level by using a paired t-test.

> Random samples of 30 professors of ethics and 30 professors in other disciplines (not ethics) were asked how many days it had been since they contacted their mothers; this included phone calls and face-to-face meetings. Professors whose mothers were not

> Many people believe that healthy people typically have a body temperature of 98.6°F. We took a random sample of 10 people and found the following temperatures: 98.4, 98.8, 98.7, 98.7, 98.6, 97.2, 98.4, 98.0, 98.3, and 98.0 Use the sign test to test the h

> McDonald’s claims that its ice cream cones typically weigh 3.18 ounces (converted from grams). Here are the weights, in ounces, of cones purchased on different days from different servers: 4.2, 3.6, 3.9, 3.4, and 3.3 Carry out a sign test to determine wh

> In exercise 13.24 you compared credit card debts for college men and women using the Mann-Whitney test to compare medians. We’ll use the same data again, but this time you will apply a randomization test to determine whether men and wom

> Are women happier than men? A StatCrunch survey asked respondents to select a number from 1 (lowest) to 100 (highest) to measure their level of happiness. The sample mean for the 297 females was 71.15, and the sample mean for the 380 males was 67.08. To

> A StatCrunch survey was done asking what percentage of liquid intake was in the form of soda. Figure A shows the output given. a. Figure B is a histogram of the percentage for the females. Describe the shape of the distribution of the sample, and comment

> A StatCrunch survey of happiness measured the happiness level for males and females. Each person selected a number from 1 (lowest) to 100 (highest) to measure her or his level of happiness. Figure A shows the output for a Mann-Whitney test to compare the

> The California Department of Education assesses progress of K–12 students in meeting grade level standards in English/Language Arts and Mathematics yearly. A regression analysis was performed using 2016 assessment data from a sample of

> Data were collected showing the gestation period (in days) and the average longevity (in years) for 32 animals. Assume that all conditions of the linear regression model hold. The data are available on this text’s website. a. Make a scatterplot with gest

> Figure A shows a scatterplot with the regression line for predicting the father’s education from the mother’s education for a random sample of 29 students. Figure B shows the confidence interval and the prediction inte

> Figure A shows a scatterplot with the regression line for the ages and weights of a random sample of 19 college baseball players. Figure B gives a prediction (Fit), a prediction interval, and a confidence interval for a new observation at 20 years old. a

> Data were collected on the weights of 25 male baseball players and 25 male soccer players. Assume that these are random samples from all college baseball and soccer players. Refer to the Mann-Whitney output. Assume the shapes and spreads of the two distr

> Cell phone bills (rounded to the nearest dollar) for the most recent month for random samples of college men (M) and college women (F) were studied. Histograms for the numbers of dollars for men and women (A) and output from a Mann-Whitney test (B) are g

> Typically, do men and women sleep different amounts? At a small private college in California, a random sample of students were asked how many hours of sleep they got last night. The figure shows the output for a Mann-Whitney test. Test the alternative h

> Is there a difference in the runs scored by winning teams in the American League and the National League in professional baseball? The winning scores for all games played on two randomly selected days were recorded and the league of the winning team was

> A statistics student who was interested in credit card debt asked a random sample of students for the total amount of their credit card debt. We eliminated the two women and the one man who had a debt of 0, which left 18 women and 19 men. a. By looking a

> A researcher was interested in the ethics of eating meat, so he studied and compared ethicists (philosophy professors who taught ethics) with professors who taught other subjects to find out whether ethicists eat less meat (Schwitzgebel and Rust 2009). T

> Figure A shows information about a random sample of students’ math SAT scores and GPAs at an unidentified four-year college. a. Use the formula on the graph to predict the GPA for a person with a math SAT score of 600. b. Figure B shows

> Figure A contains the selling price and area (in square feet) of 81 recently sold homes in a region where a buyer wants to purchase a home. a. Use the equation to estimate the price of a home with 2500 square feet. b. The buyer wants to know the uncertai

> Excessive lead levels can negatively affect brain functions; lead poisoning is particularly dangerous to children. A study was conducted to find out whether children of battery factory workers had higher levels of lead in their blood than a matched group

> Chicago public libraries collect data on the number of visitors and the number of library computer wifi sessions. A regression analysis was conducted using yearly totals for 2013. Assume the conditions for the linear model regression model are satisfied.

> The weight of trash (in pounds) produced by a household and the number of people living in the household were obtained for 13 houses. Refer to the Minitab regression output. Assume that all the conditions necessary for regression analysis are met. a. Wha

> Refer to exercise 14.17 and the output given. a. Identify the slope. Explain what it would mean if the slope were 0. b. Test the hypothesis that the slope is 0 using the output. Show all the steps, and use a significance level of 0.05. The statistics for

> Each of 29 randomly sampled community college students reported the number of years of formal education for his or her mother and father. For example, a value of 12 means that the parent completed high school but had no further education. (The numbers ra

> Do movies with bigger budgets tend to make more money? The following output shows the regression analysis on movie budgets and box office gross (how much money the movie made) for a sample of movies released in 2016. Use the output to test if the slope i

> Is there a correlation between state and federal spending on education? The following output shows the regression analysis on state and federal spending on education from a sample of states. Assume the conditions for the linear regression model are satis

> A student was interested in comparing textbook prices at two universities. She matched the textbooks by subject and compared prices from the University of California at Santa Barbara (UCSB), which is on the quarter system (10 weeks) and California State

> A random sample of the ages of 14 brides and their grooms showed that in 10 of the pairs the grooms were older, in 1 pair they were the same age, and in 3 pairs the bride was older. Perform a sign test with a significance level of 0.05 to test the hypoth

> Refer to exercise 13.19. This time, the data (beats per minute) came from female students before and after the scream. Perform a sign test to see whether the pulse rate went up significantly, using a significance level of 0.05 and treating the sample as

> Students in a statistics class were asked to measure their resting pulse rates. After that, the instructor unexpectedly screamed and ran from one side of the class to the other. Students again measured their pulse rates. The pulse rates (in beats per min

> In the past, some people believed it was easier to read words printed on colored paper than words printed on white paper, while other people believed it was easier to read words printed on white paper. To test these theories, researchers asked a sample o

> Suppose you had to identify the color of ink for a series of printed words, but the printed word appeared in a color of ink that did not match the name of the color. For example, if you were shown “RED” then you should

> Dr. Kirkland R. Gable (in Schwitzgebel 1964) studied 20 male juvenile delinquents who had each spent 6 months or more in a Massachusetts juvenile detention center. He wondered whether simply asking the juvenile delinquents to talk would help them stay ou

> Figure A shows a scatterplot for the U.S. population (in millions) from 1950 to 1990. Figure B shows a residual plot for the same data. The linear model based on these data for predicting the U.S. population given the year is also given. Should the linea

> A Nielsen poll asked people the number of hours of television they watched in the last week. Assume that Nielsen obtained a random sample. We are analyzing the data for the 39 college students in the sample. The figure shows a dotplot of the distribution

> A statistics student was interested in the amount of time that community college students exercise each week. He gathered data from a random sample of students at his community college and excluded those who did not exercise (those who reported 0 hours p

> A statistics student conducted a survey to determine how much time students at her school spent getting ready to leave the house after they got up in the morning. Figure A shows a histogram of the times for men. Assume that we have a random sample of 20

> A consumer wanted to estimate her average monthly credit card debt. She took a random sample of monthly credit card statements and recorded the total monthly balance. A histogram of the balances is shown: A 95% confidence interval for the mean credit car

> a. Find the geometric mean for the numbers 125, 260, 1000, and 15000 by using the following steps: i. Report the log of each number. Round to 1 decimal place as needed. ii. Average the 3 logs found in part a. iii. Find the antilog of the average by raisi

> a. Find the geometric mean for the numbers 10, 1000, and 10000 by using the following steps: i. Find the log of each number. ii. Average the 3 logs found in part a and report the value. iii. Find the antilog of the average by raising 10 to the power obta

> a. Find the log (base 10) of each number. Round off to one decimal place as needed. 10, 10000, 1500, 5 b. The following numbers are in log units. Do the back transformation by finding the antilog (base 10) of these numbers. Round off to one decimal place

> a. Find the log (base 10) of each number. Round off to one decimal place as needed. 10, 100, 1000, 6500 b. The following numbers are in log units. Do the back transformation by finding the antilog (base 10) of these numbers. Round off to one decimal plac

> According to home-water-works.org, the average shower in the United States lasts 8.2 minutes. Assume the standard deviation of shower times is 2 minutes and the distribution of shower times is right-skewed. Which of the following questions can be answere

> Assume women’s heights are approximately Normally distributed with a mean of 65 inches and a standard deviation of 2.5 inches. Which of the following questions can be answered using the Central Limit Theorem for sample means as needed? If the question ca

> Three independent random samples of full-time college students were asked how many hours per week they studied outside of class. Their responses and their majors are shown in the table. Test the hypothesis that the mean number of hours studying varies by

> A random sample of 50 12th-grade students was asked how long it took to get to school. The sample mean was 16.2 minutes, and the sample standard deviation was 12.3 minutes. (Source: AMSTAT Census at School) a. Find a 95% confidence interval for the popul

> A random sample of 25 men’s resting pulse rates shows a mean of 72 beats per minute and a standard deviation of 13. a. Find a 95% confidence interval for the population mean pulse rate for men, and report it in a sentence. You may use t

> The figure shows side-by-side boxplots of the number of hours per week that University of California, Los Angeles (UCLA) students spent listening to music. Minitab output for ANOVA is also shown. Check whether the conditions for ANOVA hold. If not, state

> Here are the conviction rates with the “stand your ground” data mentioned in the previous exercise. “White shooter on nonwhite” means that a white assailant shot a minority victim. a

> In July 2013, Jeff Witmer obtained a data set from the Tampa Bay Times after the Zimmerman case was decided. Zimmerman shot and killed Trayvon Martin (an unarmed black teenager) and was acquitted. The data set concerns “stand your groun

> Refer to the description in exercise 10.71. There were 22 trials with only cockroaches (no robots) that went under one shelter. In 16 of these 22 trials, the group chose the darker shelter, and in 6 of the 22 the group chose the lighter shelter. There we

> Cockroaches tend to rest in groups and prefer dark areas. In a study by Halloy et al. published in Science Magazine in November 2007, cockroaches were introduced to a brightly lit, enclosed area with two different available shelters, one darker than the

> Random samples of 12th-grade students from California, Utah, and New York were asked how long it took them to get to school (in minutes). StatCrunch output for an ANOVA is shown, along with the Tukey HSD confidence intervals. Using the confidence interva

> Three million people in Sweden are trained in CPR, which is more than 30% of the population. The data set is summarized below. A 2015 study by Hasselqvist-Ax et. al reported in the New England Journal of Medicine examined the relationship between bystand

> An 2017 NPR/Marist poll asked a random sample of Americans if they had personally experienced sexual harassment in the workplace. The results are shown in the following table. a. Find the percentage in each group who had personally experienced sexual har

> According to the National Institute of Mental Health, Social Anxiety Disorder (SAD) is a mental health disorder that affects up to 7% of the population of the United States. Because many SAD patients experience inadequate symptom relief with available tr

> The 3-year recidivism rate in the United States is about 68%, which means that 68% of released U.S. prisoners return to prison within 3 years of release. There have been many attempts to reduce the recidivism rate. Suppose you want to determine whether e

> In Montreal, Canada, an experiment was done with parents of children who were thought to have a high risk of committing crimes when they became teenagers (Tremblay et al., 1996). Some of the families were randomly assigned to receive parental training, a

> The Perry Preschool Project discussed in exercises 10.39 to 10.41 found that 8 of the 58 students who attended preschool had at least one felony arrest by age 40 and that 31 of the 65 students who did not attend preschool had at least one felony arrest (

> In a 2017 study published at PLOS.org, researchers investigated the effect of music on creativity (Ritter and Ferguson 2017). Subjects were recruited for the study using an online research participation system at a university. Four pieces of music were s

> Refer to exercise 12.44. How could you investigate whether consuming fish at least two times per week causes decreased disease activity in rheumatoid arthritis patients? Describe the design of a study assuming you have 100 rheumatoid arthritis patients i

> Refer to exercise 12.43. How could you investigate whether participation in a Yoga and Meditation based Lifestyle Intervention (YMLI) caused the improved cellular biomarkers associated in this study? Describe the design of a study assuming you have 200 h

> Does frequent use of acetaminophen lead to asthma-related complications among children? Excerpts from the abstract of a study published in The New England Journal of Medicine about this are given (Sheehan et al. 2016). Read them and then answer the quest

> A study reported in the New England Journal of Medicine was conducted to compare outcomes for radial arterial grafts and saphenous-vein grafts in coronary artery bypass surgeries (Gaudino et al. 2018). Read this excerpt from the study abstract and answer

> Critically ill patients are often given intravenous fluids in hospital, either in the form of balanced crystalloids or saline solutions. In a 2018 study published in The New England Journal of Medicine, researchers investigated which of these approaches

> In a 2018 study by Hurst and Fukuda published in BMJ Open, researchers in Japan surveyed 59,717 participants in Japan who had Type 2 diabetes. Participants were asked to rate their eating speed as Slow, Normal, or Fast. Researchers found that those who r

> StatCrunch surveyed users on happiness. Each respondent scored herself or himself between 1 (least happy) and 100 (most happy). We would like to determine whether age category has an effect on happiness for users of StatCrunch. Assume the data are from a

> In a study done on a random sample of employees at a company, the employees wrote down how many hours they slept and their health status. StatCrunch output for an ANOVA is shown. Test the hypothesis that health status and number of hours of sleep are ass

> The StatCrunch output shows the ANOVA results for testing whether there is an association between the number of hours of TV watched per week and age group: 50 and over (AdultTV), college students (TeenTV), and grade school students (ChildTV). Test the hy

> Professors of ethics (Eth), professors of philosophy (Phil), and professors in fields other than philosophy or ethics (Other) were asked what percentage of income they actually donated to charity. Assume the professors are randomly sampled. The data are

> Professors of ethics (Eth), professors of philosophy (Phil), and professors in fields other than philosophy or ethics (Other) were asked what percentage of their income professors should donate to charity. Assume the professors are randomly sampled from

> A random sample of people were asked whether they were athletic, moderately athletic (Mod), or not athletic (NotAth). Then they were tested for reaction speed. Reaction speed was measured indirectly, through reaction distance, as follows: A vertical mete

> When the draft lottery for military service in the Vietnam War was conducted, officials “randomly” selected birthdays. For example, September 14 was selected first, and that date was assigned the rank of 1. If March 7