A political scientist wants to know how a random sample of 18- to 25-year-olds feel about Democrats and Republicans in Congress. She obtains a random sample of 1030 registered voters 18 to 25 years of age and asks, “Do you have favorable/ unfavorable [rotated] opinion of the Democratic/Republican [rotated] party?” Each individual was asked to disclose his or her opinion about each party.
> The following data represent the daily rental for a compact automobile charged by two car rental companies, Thrifty and Hertz, in ten locations. Test whether Thrifty is less expensive than Hertz at the = 0.1 level of significance. Note: A normal probab
> The manufacturer of hardness testing equipment uses steel-ball indenters to penetrate a metal that is being tested. However, the manufacturer thinks it would be better to use a diamond indenter so that all types of metal can be tested. Because of differe
> A quality-control manager at an amusement park feels that the amount of time that people spend waiting in line for the American Eagle roller coaster is too long. To determine if a new loading/unloading procedure is effective in reducing wait time in line
> To test the belief that sons are taller than their fathers, a student randomly selects 13 fathers who have adult male children. She records the height of both the father and son in inches and obtains the following data. Does the evidence suggest that son
> A Secchi disk is an 8-inch-diameter weighted disk that is painted black and white and attached to a rope. The disk is lowered into water and the depth (in inches) at which it is no longer visible is recorded. The measurement is an indication of water cla
> It is a commonly held belief that SUVs are safer than cars. If an SUV and car are in a collision, does the SUV sustain less damage (as suggested by the cost of repair)? The Insurance Institute for Highway Safety crashed SUVs into cars, with the SUV movin
> Suppose you are reading an article at psychcentral.com and the following text appears in a pop-up window: What tactic is the company using to increase the response rate for its survey?
> In an experiment conducted online at the University of Mississippi, study participants are asked to react to a stimulus. In one experiment, the participant must press a key on seeing a blue screen and reaction time (in seconds) to press the key is measur
> The following data represent the muzzle velocity (in feet per second) of rounds fired from a 155-mm gun. For each round, two measurements of the velocity were recorded using two different measuring devices, with the following data obtained: (a) Why are t
> In a prospective cohort study, 20 patients with alopecia (hair loss) had platelet-rich plasma (PRP) injected in their scalps. After three months, the mean difference in hair density (after before) was 170.70 hairs per square centimeter with a standard de
> A researcher wishes to determine the effects of alcohol on people’s reaction time to a stimulus. She randomly divides 100 people aged 21 or older into two groups. Group 1 is asked to drink 3 ounces of alcohol, while group 2 drinks a placebo. Both drinks
> A sociologist wishes to compare the annual salaries of married couples in which both spouses work and determines each spouse’s annual salary.
> A sampling method is _____ when the individuals selected for one sample are used to determine the individuals in the second sample.
> A sampling method is ______ when the individuals selected for one sample do not dictate which individuals are selected to be in a second sample.
> Explain the difference between an independent and dependent sample
> Why do we use a pooled estimate of the population proportion when testing a hypothesis about two proportions? Why do we not use a pooled estimate of the population proportion when constructing a confidence interval for the difference of two proportions?
> On April 12, 1955, Dr. Jonas Salk released the results of clinical trials for his vaccine to prevent polio. In these clinical trials, 400,000 children were randomly divided in two groups. The subjects in group 1 (the experimental group) were given the va
> Consider the following two questions: (a) Do you believe that the government should or should not be allowed to prohibit individuals from expressing their religious beliefs at their place of employment? (b) Do you believe that the government should or sh
> Stock fund managers are investment professionals who decide which stocks should be part of a portfolio. In an article in the Wall Street Journal (“Not a Stock-Picker’s Market,” WSJ, January 25, 2014), the performance of stock fund managers was considered
> An educator wants to determine the difference between the proportion of males and females who have completed four or more years of college. What sample size should be obtained if she wishes the estimate to be within 2 percentage points with 90% confidenc
> A physical therapist wants to determine the difference in the proportion of men and women who participate in regular, sustained physical activity. What sample size should be obtained if she wishes the estimate to be within 3 percentage points with 95% co
> A random sample of single males and single females (aged 21 to 76) was obtained by a group called Singles in America. The sample includes those currently separated, divorced, or widowed. The subjects were given a trait and asked to respond whether the tr
> Psychologists asked students to read two sentences about hypothetical politicians. One group of students read, “Last year, Mark was having an affair with his assistant and was taking hush money from a prominent constituent.” Let’s call this sentence A. S
> In the Sullivan Statistics Survey I, respondents were asked, “Would you be willing to pay higher taxes if the tax revenue went directly toward deficit reduction?” Treat the respondents as a simple random sample of adult Americans. The results of the surv
> The data set “Tornadoes_2017” located at www.pearsonhighered.com/ sullivanstats contains a variety of variables that were measured for all tornadoes in the United States in 2017. (a) Is there a difference in the proportion of F0 tornadoes in Texas versus
> In March 2003, the Pew Research Group surveyed 1508 adult Americans and asked, “Do you believe the United States made the right or wrong decision to use military force in Iraq?” Of the 1508 adult Americans surveyed, 1086 stated the United States made the
> OPDIVA is a drug developed by Brystol-Meyers Squib that is meant to treat metastatic melanoma, which is the worst form of skin cancer. Survival rates for patients with this cancer are 6 to 10 months. Historically, patients with metastatic melanoma were t
> In clinical trials for treatment of a skin disorder, 642 of 2105 patients receiving the current standard treatment were cured of the disorder and 697 of 2115 patients receiving a new proposed treatment were cured of the disorder. (a) Does the new procedu
> Consider the following two questions: (a) Currently, social media companies, such as Facebook, profit by selling user data. Do you believe the government should regulate the ability of social media companies to sell user data? (b) Would you be willing to
> In clinical trials of the allergy medicine Clarinex (5 mg), 3307 allergy sufferers were randomly assigned to either a Clarinex group or a placebo group. It was reported that 50 out of 1655 individuals in the Clarinex group and 31 out of 1652 individua
> Researchers at Harris Interactive wondered if there was a difference between males and females in regard to whether they typically buy name-brand or store-brand products. They asked a random sample of males and females the following question: “For each o
> Researchers at Harris Interactive wondered if there was a difference between males and females in regard to some common annoyances. They asked a random sample of males and females, the following question: “Are you annoyed by people who repeatedly check t
> The body mass index (BMI) of an individual is a measure used to judge whether an individual is overweight or not. A BMI between 20 and 25 indicates a normal weight. In a survey of 750 men and 750 women, the Gallup organization found that 203 men and 270
> The Harris Poll conducted a survey in which they asked, “How many tattoos do you currently have on your body?” Of the 1205 males surveyed, 181 responded that they had at least one tattoo. Of the 1097 females surveyed, 143 responded that they had at least
> The Pew Research Group conducted a poll in which they asked, “Are you in favor of, or opposed to, executing persons as a general policy when the crime was committed while under the age of 18?” Of the 580 Catholics surveyed, 180 indicated they favored cap
> In October 1947, the Gallup organization surveyed 1100 adult Americans and asked, “Are you a total abstainer from, or do you on occasion consume, alcoholic beverages?” Of the 1100 adults surveyed, 407 indicated that they were total abstainers. In a re
> In randomized, double-blind clinical trials of Prevnar, infants were randomly divided into two groups. Subjects in group 1 received Prevnar, while subjects in group 2 received a control vaccine. After the second dose, 137 of 452 subjects in the experimen
> The drug Prevnar is a vaccine meant to prevent certain types of bacterial meningitis, typically administered to infants around 2 months. In randomized, double-blind clinical trials of Prevnar, infants were randomly divided into two groups. Subjects in gr
> x1 = 804, n1 = 874, x2 = 892, n2 = 954, 95% confidence
> The General Social Survey asked, “About how often did you have sex in the past 12 months?” About 47% of respondents indicated they had sex at least once a week. In an internet survey for a marriage and family wellness center, respondents were asked, “How
> x1 = 28, n1 = 254, x2 = 36, n2 = 301, 95% confidence
> x1 = 109, n1 = 475, x2 = 78, n2 = 325, 99% confidence
> x1 = 368, n1 = 541, x2 = 421, n2 = 593, 90% confidence
> Test whether / /
> Test whether / /
> Test whether / /
> Test whether / /
> A psychologist wants to know whether subjects respond faster to a go/no go stimulus or a choice stimulus. With the go/no go stimulus, subjects must respond to a particular stimulus by pressing a button and disregard other stimuli. In the choice stimulus,
> An educator wants to determine whether a new curriculum significantly improves standardized test scores for third grade students. She randomly divides 80 third-graders into two groups. Group 1 is taught using the new curriculum, while group 2 is taught u
> Surveys tend to suffer from low response rates. Based on past experience, a researcher determines that the typical response rate for an e-mail survey is 40%. She wishes to obtain a sample of 300 respondents, so she e-mails the survey to 1500 randomly sel
> The Gallup Organization asked 1050 randomly selected adult Americans age 18 or older who consider themselves to be religious, “Do you believe it is morally acceptable or morally wrong [rotated] to conduct medical research using stem cells obtained fr
> A simple random sample of size n = 200 individuals with a valid driver’s license is asked if they drive an American-made automobile. Of the 200 individuals surveyed, 115 responded that they drive an American-made automobile. Determine if a majority of th
> A simple random sample of size n = 19 is drawn from a population that is normally distributed. The sample mean is found to be 0.8, and the sample standard deviation is found to be 0.4. Test whether the population mean is less than 1.0 at the = 0.01 lev
> Researchers measured regular testosterone levels in a random sample of athletes and then measured testosterone levels prior to an athletic event. They wanted to know whether testosterone levels increase prior to athletic events.
> In 2014, of the 37 million borrowers who have outstanding student loan balances, 14% have at least one past due student loan account. A researcher with the United States Department of Education believes this proportion has increased since then. Sourc
> According to the Pew Research Center, 55% of adult Americans support the death penalty for those convicted of murder. A social scientist wondered whether a higher proportion of adult Americans with at least a bachelor’s degree support the death penalty f
> An official with the Internal Revenue Service wished to estimate the proportion of high-income (greater than $100,000 annually) earners who under-reported their net income (and, therefore, their tax liability).
> A researcher wanted to estimate the average length of time mothers who gave birth via Caesarean section spent in a hospital after delivery of the baby.
> An investigator with the Food and Drug Administration wanted to determine whether a typical bag of potato chips contained less than the 16 ounces claimed by the manufacturer.
> Suppose you wish to determine if the mean IQ of students on your campus is different from the mean IQ in the general population, 100. To conduct this study, you obtain a simple random sample of 50 students on your campus, administer an IQ test, and recor
> To determine the public’s opinion of the police department, the police chief obtains a cluster sample of 15 census tracts within his jurisdiction and samples all households in the randomly selected tracts. Uniformed police officers go door to door to con
> A survey from the Gallup organization asked, “What do you think is the ideal number of children for a family to have?” Go to www.pearsonhighered.com/sullivanstats to obtain the data file 10_4_18 using the file format of your choice for the version of the
> According to Crestmont Research, the stock market has been up in 53.7% of all trading days over the past 50 years. A stock is up if the price per share increases in value day-over-day. An investor wondered whether the proportion of days Amazon stock was
> Suppose the mean wait-time for a telephone reservation agent at a large airline is 43 seconds. A manager with the airline is concerned that business may be lost due to customers having to wait too long for an agent. To address this concern, the manager d
> Politicians often form their positions on various policies through polling. Suppose the U.S. Congress is considering passage of a tax increase to pay down the national debt and national polls suggest the general population is equally split on the matter.
> Student loan debt has reached record levels in the United States. In a random sample of 100 individuals who have student loan debt, it was found the mean debt was $23,979 with a standard deviation of $31,400. Data based on results from the Federal Reserv
> According to the research firm Toluna, the proportion of individuals who text while driving is 0.26. Suppose a random sample of 60 individuals are asked to disclose if they text while driving. Results of the survey are shown next, where 0 indicates no an
> According to the National Sleep Foundation, children between the ages of 6 and 11 years should get 10 hours of sleep each night. In a survey of 56 parents of 6 to 11 year olds, it was found that the mean number of hours the children slept was 8.9 with a
> The Environmental Protection Agency (EPA) states that a 2013 Kia Optima should get 28 miles per gallon, on average. The website www.fueleconomy.gov allows users to report the miles per gallon that they get on their vehicle. Treat the following data as a
> According to the Federal Reserve Bank of Boston, among individuals who had credit cards in 2014, the mean number of cards was 3.5. Treat the individuals who have credit cards in the SullivanStatsSurveyI as a random sample of credit card holders. Go to ww
> Pass rates for Intermediate Algebra at a community college are 52.6%. In an effort to improve pass rates in the course, faculty of a community college develop a mastery- based learning model where course content is delivered in a lab through a computer p
> Suppose you are conducting a survey regarding illicit drug use among teenagers in the Baltimore school district. You obtain a cluster sample of 12 schools within the district and sample all sophomore students in the randomly selected schools. The survey
> In October 1945, the Gallup organization asked 1487 randomly sampled Americans, “Do you think we can develop a way to protect ourselves from atomic bombs in case other countries tried to use them against us?” with 788 responding yes. Did a majority of Am
> A psychologist obtains a random sample of 20 mothers in the first trimester of their pregnancy. The mothers are asked to play Mozart in the house at least 30 minutes each day until they give birth. After 5 years, the child is administered an IQ test. We
> A simple random sample of size n = 320 adults was asked their favorite ice cream flavor. Of the 320 individuals surveyed, 58 responded that they preferred mint chocolate chip. Do less than 25% of adults prefer mint chocolate chip ice cream? Use the = 0
> A simple random sample of size n = 40 is drawn from a population. The sample mean is found to be 108.5, and the sample standard deviation is found to be 17.9. Is the population mean greater than 100 at the = 0.05 level of significance?
> A simple random sample of size n = 65 is drawn from a population. The sample mean is found to be 583.1, and the sample standard deviation is found to be 114.9. Is the population mean different from 600 at the = 0.1 level of significance?
> A simple random sample of size n = 15 is drawn from a population that is normally distributed. The sample mean is found to be 23.8, and the sample standard deviation is found to be 6.3. Is the population mean different from 25 at the = 0.01 level of si
> To test /a simple random sample of size n = 23 is obtained from a population that is known to be normally distributed. (a) If / = 104.8 and s = 9.2, compute the test statistic. (b) If the researcher decides to test this hypothesis at the = 0.01 level o
> To test /, a simple random sample of size n = 25 is obtained from a population that is known to be normally distributed. (a) If / = 42.3 and s = 4.3, compute the test statistic. (b) If the researcher decides to test this hypothesis at the = 0.1 level o
> To test /a simple random sample of size n = 24 is obtained from a population that is known to be normally distributed. (a) If / = 47.1 and s = 10.3, compute the test statistic. (b) If the researcher decides to test this hypothesis at the = 0.05 level o
> (a) Determine the critical value for a right-tailed test of a population mean at the = 0.1 level of significance with 22 degrees of freedom. (b) Determine the critical value for a left-tailed test of a population mean at the = 0.01 level of significa
> A textbook publisher wants to determine what percentage of college professors either require or recommend that their students purchase textbook packages with supplemental materials. The publisher sends surveys by e-mail to a random sample of 320 faculty
> Phone number
> (a) Determine the critical value for a right-tailed test of a population mean at the = 0.01 level of significance with 15 degrees of freedom. (b) Determine the critical value for a left-tailed test of a population mean at the = 0.05 level of signific
> The life expectancy of a male during the course of the past 100 years is approximately 27,725 days. Go to Wikipedia.com and download the data that represent the life span of chief justices of Canada for those who have died. Conduct a test to determine wh
> Explain the difference between statistical significance and practical significance.
> The procedures for testing a hypothesis regarding a population mean are robust. What does this mean?
> The head of institutional research at a university believes that the mean age of full-time students is declining. In 1995, the mean age of a full-time student was known to be 27.4 years. After looking at the enrollment records of all 4934 full-time stude
> It is well-documented that watching TV, working on a computer, or any other activity involving artificial light can be harmful to sleep patterns. Researchers wanted to determine if the artificial light from e-Readers also disrupted sleep. In the study, 1
> The exponential probability distribution can be used to model waiting time in line or the lifetime of electronic components. Its density function is skewed right. Suppose the wait time in a line can be modeled by the exponential distribution with = =
> Simulate drawing 100 simple random samples of size n = 15 from a population that is normally distributed with mean 100 and standard deviation 15. (a) Test the null hypothesis /for each of the 100 simple random samples. (b) If we test this hypothesis at t
> The mean IQ score of humans is 100. Suppose the director of Institutional Research at Joliet Junior College (JJC) obtains a simple random sample of 40 JJC students and finds the mean IQ is 103.4 with a standard deviation of 13.2. (a) Consider the hypothe
> The data set “Tornadoes_2017” located at www.pearsonhighered.com/sullivanstats contains a variety of variables that were measured for all tornadoes in the United States in 2017. (a) Compute the population mean length of a tornado in the United States in
> A magazine is conducting a study on the effects of infidelity in a marriage. The editors randomly select 400 women whose husbands were unfaithful and ask, “Do you believe a marriage can survive when the husband destroys the trust that must exist between
> The manufacturer of a daily dietary supplement claims that its product will help people lose weight. The company obtains a random sample of 950 adult males aged 20 to 74 who take the supplement and finds their mean weight loss after 8 weeks to be 0.9 pou
> A math teacher claims that she has developed a review course that increases the scores of students on the math portion of the SAT exam. Based on data from the College Board, SAT scores are normally distributed with = 515. The teacher obtains a random
> Problem 28
> Problem 27
> Problem 26
