Question: According to a 2018 Money magazine article,

> 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

> A 2017 study reported in the Harvard Health Blog investigated the association between fish consumption and disease activity in 176 rheumatoid arthritis patients (Tedeschi et al. 2017). Frequency of fish consumption was assessed through a questionnaire. R

> Information was gathered on the starting median salary for students who attended four different types of colleges. Assume the samples are random and Normal. Test the hypothesis that the population means are equal for all the types of colleges. Show all f

> In the study described in 10.35 researchers also asked survey respondents if they had heard of the HPV vaccine. Data are shown in the table. Test the hypothesis that knowledge of the vaccine and race are associated. Use a 0.05 significance level.

> A vaccine is available to prevent the contraction of human papillomavirus (HPV). The Centers for Disease Control and Prevention recommends this vaccination for all young girls in two doses. In a 2015 study reported in the Journal of American College Heal

> A 2018 Pew Research poll recorded respondents political affiliation and generation. A summary of the results for Millennials and GenXers are shown in the following table, assuming a sample size of 200. Test the hypothesis that political party affiliation

> A 2018 Pew Research poll recorded respondents political affiliation and education attainment. A summary of the data is shown in the following table. Test the hypothesis that political party affiliation and educational attainment are associated at the 0.0

> In a 2018 article published in The Lancet, Kappos et al. studied the effect of the drug siponimod in treating patients with secondary progressive multiple sclerosis (SPMS) using a double-blind, randomized, controlled study. Of the 1099 patients given the

> In a 2018 article published in The Lancet, Sprigg et al. studied the effect of tranexamic acid in treating patients with intracerebral hemorrhages using a randomized, placebo-controlled trial. Of the 1161 subjects treated with tranexamic acid, 383 suffer

> The 2018 Pew Research poll in exercise 10.43 also reported responses by political party. Survey results found 45% of Republicans and 69% of Democrats supported marijuana legalization. a. Use these results to fill in the following two-way table with the c

> A 2018 Pew Research poll asked a random sample of Millennials and GenXers if they supported legalization of marijuana. Survey results found 70% of Millennials and 66% of GenXers supported marijuana legalization. a. Use these results to fill in the follow

> Exercise 10.11 on artery disease in mummies indicated that 9 out of 16 mummies showed heart disease (hardening of the arteries). Test the hypothesis that the population proportion of mummies with hardening of the arteries is not the same as in the modern

> A 2017 study explored the impact of Yoga and Meditation based Lifestyle Intervention (YMLI) on cellular aging in healthy individuals (Tohlahunase et al. 2017). Ninety-six healthy individuals were enrolled in the 12-week YMLI course, which consisted of yo

> Professional musicians listened to five violins being played, without seeing the instruments. One violin was a Stradivarius, and the other four were modern-day violins. When asked to pick the Stradivarius (after listening to all five), 39 got it right an

> The table shows the results of rolling a six-sided die 120 times. Test the hypothesis that the die is not fair. A fair die should produce equal numbers of each outcome. Use the four-step procedure with a significance level of 0.05, and state your conclus

> See exercise 10.21 for an explanation of playing with the dreidel. This time the family used a plastic dreidel and got the following outcomes. The four outcomes are believed to be equally likely (that is, has a uniform probability distribution). Determin

> When playing Dreidel, (see photo) you sit in a circle with friends or relatives and take turns spinning a wobbly top (the dreidel). In the center of the circle is a pot of several foil-wrapped chocolate coins. If the four-sided top lands on the Hebrew le

> In 2018 Pew Research reported that 11% of Americans do not use the Internet. Suppose in a random sample of 200 Americans, 26 reported not using the Internet. Using a chi-square test for goodness-of-fit, test the hypothesis that the proportion of American

> A penny was spun on a hard, flat surface 50 times, and the result was 15 heads and 35 tails. Using a chisquare test for goodness of fit, test the hypothesis that the coin is biased, using a 0.05 level of significance.

> The mean age of all 118 used Toyota vans for sale (see exercise 9.16) was 3.1 years with a standard deviation of 2.7 years. The distribution of ages is right skewed. For a statistics project, a student randomly selects 35 vans from this data set and find

> One histogram shows the distribution of costs for all used Toyota Sienna vans for sale within a 100 mile radius of San Leandro, CA, for a day in 2018. The other three graphs show distributions of means from random samples taken from this population based

> According to a 2018 Money magazine article, Maryland has one of the highest per capita incomes in the United States, with an average income of $75,847. Suppose the standard deviation is $32,000 and the distribution is right-skewed. A random sample of 100

> In a 2017 study published in Scientific Reports, researchers (Mubanga et al. 2017) concluded that “dog ownership was associated with a lower risk of incident cardiovascular disease in single-person households and with lower cardiovascular and all-cause m

> Use the information for exercise 11.20. a. Which class had the highest sample mean number of TV hours, and which class had the lowest sample mean? (1 is for freshman, 2 is for sophomore, and so on.) b. Write out the null and alternative hypotheses for th

> Use the information for exercise 11.19. a. Which class had the highest sample mean, and which class had the lowest sample mean? (1 is for freshman, 2 is for sophomore, and so on.) b. Write out the null and alternative hypotheses for the effect of class o

> Test the hypothesis that people with different marital statuses differ in mean systolic blood pressure, using a significance level of 0.05. Refer to the Stat- Crunch output from NHANES data. a. Write the null and alternative hypotheses for the associatio

> Refer to the StatCrunch output from National Health and Nutrition Examination Survey (NHANES) data, which shows the association between marital status and cholesterol. Assume the population distributions are close enough to Normal to justify using ANOVA.

> One of the authors collected data from a class to see whether humans made selections randomly, as a random number generator would. Each of 38 students had to pick an integer from one to five. The data are summarized in the table. A true random number gen

> Suppose you had to identify the color of ink for a series of printed words that spelled out a color that did not match the ink color. For example, what color ink is used in the word RED? This might take longer than identifying the color when the ink and

> Some people believe that it is easier to read words printed on colored paper than words printed on white paper. To test this theory, statistics student Paula Smith collected data. Subjects were timed as they read a passage printed in black ink on a sheet

> Repeat the chi-square test (all four steps) from exercise 10.23, but this time assume that you got exactly 20 outcomes in each of the six categories. Refer to the figure. Explain.

> In a 2017 study, researchers investigated the effect of dietary improvement on adults with moderate to severe depression (Jacka et al. 2017). Subjects were randomly assigned to a treatment group consisting of seven individual nutritional consulting sessi

> Suppose you grow tomato plants in a greenhouse and sell the tomatoes by weight, so the amount of money you make depends on plants producing a large total weight of tomatoes. You want to determine which of two fertilizers will produce a heavier harvest of

> Phubbing is the practice of ignoring one’s companion or companions in order to pay attention to one’s phone or other mobile device. In the conclusion of a 2017 study published in Personality and Individual Differences, researchers (Wang et al. 2017) conc

> Suppose that you want to determine whether the use of one aspirin per day for people age 50 and older reduces the chance of heart attack. You have 200 people available for the study: 100 men and 100 women. You suspect that aspirin might affect men and wo

> Suppose you want to compare the effectiveness of the flu vaccine in preventing the flu using one of two different forms: nasal spray versus injection. Suppose you have 60 subjects available of different ages, and you suspect that age might have an effect

> Speed skating is a sport in which it is important to have a suit that minimizes wind drag as much as possible, as the difference between winning and losing a race can be as small as a thousandth of a second. In the 2014 Winter Olympics, U.S. speed skater

> We counted ones, twos, threes, fours, and fives from a few lines of a random number table, and we should expect to get equal numbers of each. (We ignored the sixes, sevens, eights, nines, and zeros.) There were 14 ones, 12 twos, 16 threes, 11 fours, and

> Researchers are interested in testing whether a video game that is designed to increase brain activity actually works. To test this, they plan to randomly assign subjects to either the treatment group (spend 15 minutes per day playing the game) or a cont

> Suppose an SAT tutoring company really can improve SAT scores by 10 points, on average. A competing company, however, uses a more intense tutoring approach and really can improve SAT scores by 15 points, on average. Suppose you’ve been hired by both comp

> Refer to the figure. Assume that all distributions are symmetric (therefore the sample mean and median are approximately equal) and that all the samples are the same size. Imagine carrying out two ANOVAs. The first compares the means based on samples A,

> Dravet syndrome is a complex childhood epilepsy disorder. Researchers Devinsky et al., conducted a double-blind placebo-controlled trial to determine the efficacy of the drub cannabiliol on reducing seizures in children with Dravet syndrome. One hundred

> A 2017 Pew poll asked a random sample “Are men and women basically different in how they express feelings?” The results by gender (in percentages) are shown in the table below. a. Assume the sample size for each gender

> Some sources report that the weights of full-term newborn babies have a mean of 7 pounds and a standard deviation of 0.6 pound and are Normally distributed. In the given outputs, the shaded areas (reported as p=) represent the probability that the mean w

> A random sample of 50 college first-year students (out of a total of 1000 first-years) was obtained from college records using systematic sampling. Half of those students had a campus tour with a sophomore student, and half had a tour with an instructor.

> Some sources report that the weights of full-term newborn babies have a mean of 7 pounds and a standard deviation of 0.6 pound and are Normally distributed. a. What is the probability that one newborn baby will have a weight within 0.6 pound of the mean—

> Samples of rents for one-bedroom, one-bath apartments in three cities were obtained. Assume the distribution of each population is Normal to satisfy the conditions for using ANOVA. Test the hypothesis that the mean rent for one-bedroom apartments in at l

> Based on the following output, would it be appropriate to use ANOVA to determine if the mean gas prices for one of these five cities is significantly different from that of the other cities? If so, perform the ANOVA. If not, explain why it is not appropr

> In the study referenced in exercise 10.8, researchers also asked whether or not students bought fast food at least one to two times per week. The data are reported by gender in the table. a. Find the row, column, and grand totals, and prepare a table sho

> Construct heights for 3 or more sets of twins (6 or more people). Make the twins similar, but not exactly the same, in height. Put all of the shorter twins in set A and all of the taller twins in set B. Create the numbers such that a two-sample t-test wi

> Construct two sets of body temperatures (in degrees Fahrenheit, such as 96.2 °F), one for men and one for women, such that the sample means are different but the hypothesis test shows the population means are not different. Each set should have three num

> The table shows the heights (in inches) of all the basketball players on the 2017–2018 Santa Clara University basketball team. Explain why it would be inappropriate to do a t-test with these data.

> A survey was given to StatCrunch users on the length of time for commuting and the method of commuting. Assume this is a random sample. Minitab output for one-way ANOVA is given, along with the means and standard deviations. Divide the largest standard d

> Pulse rates were taken for five people, each in three different situations: sitting, after meditation, and after exercise. Explain why it would not be appropriate to use one-way ANOVA to test whether the population mean pulse rates were associated with a

> Go back to the information in exercise 11.20. Assuming the conditions for ANOVA are met, test the hypothesis that the mean number of hours of TV varies by class, reporting the p-value and conclusion. Use the 0.05 level of significance. State your conclus

> Go back to the information in exercise 11.19. Assuming the conditions for ANOVA are met, test the hypothesis that the mean number of hours of schoolwork varies by class, reporting the p-value and conclusion. Use the 0.05 level of significance. State your

> Some software (such as SPSS) requires that ANOVA data be stacked and coded. Some software works with both stacked and unstacked data, and some (such as the TI-84) requires unstacked data. Go back to the information given in exercise 11.7. Stack and code

> The table shows the percentage of all U.S. households who are food secure, have low food security, or who have very low food security. The data are reported by area of residence. Give two reasons why it would be inappropriate to do a chi-square test to d

> The table shows the percentage of all men and women in the United States aged 18 to 44 who meet aerobic fitness guidelines. Give two reasons why a chi-square test is not appropriate for this data. (Source: 2017 World Almanac and Book of Facts)

> In a 2015 study by Nanney et al. and published in the Journal of American College Health, a random sample of community college students was asked whether they ate breakfast 3 or more times weekly. The data are reported by gender in the table. a. Find the

> A large number of surgery patients get infections after surgery, which can sometimes be quite serious. Researchers randomly assigned some surgery patients to receive a simple antibiotic ointment after surgery, others to receive a placebo, and others to r

> Suppose a polling organization asks a random sample of people if they are Democrat, Republican, or Other and asks them if they think the country is headed in the right direction or the wrong direction. If we wanted to test whether party affiliation and a

> A random sample of 12th-grade students were asked to rate the importance of reducing pollution on a scale from 0 to 1000. Responses were recorded by gender. The results of a hypothesis test are shown. Assume the conditions for using a two-sample t-test a

> State whether each of the following changes would make a confidence interval wider or narrower. (Assume that nothing else changes.) a. Changing from a 95% level of confidence to a 90% level of confidence b. Changing from a sample size of 30 to a sample s

> State whether each of the following changes would make a confidence interval wider or narrower. (Assume that nothing else changes.) a. Changing from a 90% confidence level to a 99% confidence level b. Changing from a sample size of 30 to a sample size of

> In exercise 9.31, two intervals were given for the same data, one for 95% confidence and one for 90% confidence. a. How would a 99% interval compare? Would it be narrower than both, wider than both, or between the two in width. Explain. b. If we wanted t

> Choose a t-test for each situation: one-sample t-test, two-sample t-test, paired t-test, and no t-test. a. A random sample of car dealerships is obtained. Then a student walks onto each dealer’s lot wearing old clothes and finds out how long it takes (in

> Choose a test for each situation: one-sample t-test, two-sample t-test, paired t-test, and no t-test. a. A random sample of students who transfered to a 4-year university from community colleges are asked their GPAs. Our goal is to determine whether the

> A random sample of 25 baseball players from the 2017 Major League Baseball season was taken and the sample data was used to construct two confidence intervals for the population mean. One interval was (22.0, 42.8). The other interval was (19.9, 44.0). (S

> Treatment In a 2018 study by Zhu et al. reported in The Lancet, researchers conducted an experiment to determine the efficacy and safety of the drug dorzagliatin in the treatment of patients with Type 2 diabetes. In this double-blind study, patients were

> In a 2018 study reported in The New England Journal of Medicine, Johnston et al. studied the effect of a combination of the drug clopidogrel and aspirin on reducing the rate of recurrent stroke among stroke patients. Stroke patients in the study were ran

> A 2018 Gallup poll asked college graduates if they agreed that the courses they took in college were relevant to their work and daily lives. The respondents were also classified by their field of study. If we wanted to test whether there was an associati