According to Martin Boon of ICM Limited, a polling firm in Britain, in 1995 it took 3000 to 4000 phone calls to obtain a sample of size 2000. Today, it takes over 30,000 calls. To reduce costs, more polling is done using robocalls and Internet-based polling. Robocalling to cellular telephones is illegal. How do these methods potentially lead to nonsampling error? What types of nonsampling error do you think this may lead to?
> A random sample of size n = 41 results in a sample mean of 125.3 and a sample standard deviation of 8.5. An independent sample of size n = 50 results in a sample mean of 130.8 and sample standard deviation of 7.3. Does this constitute sufficient evidence
> A random sample of n1 = 135 individuals results in x1 = 40 successes. An independent sample of n2 = 150 individuals results in x2 = 60 successes. Does this represent sufficient evidence to conclude that p1 6 p2 at the = 0.05 level of significance?
> A random sample of size n = 13 obtained from a population that is normally distributed results in a sample mean of 45.3 and sample standard deviation of 12.4. An independent sample of size n = 18 obtained from a population that is normally distributed
> A random sample of n1 = 120 individuals results in x1 = 43 successes. An independent sample of n2 = 130 individuals results in x2 = 56 successes. Does this represent sufficient evidence to conclude that p1≠ p2 at the a = 0.01 level of significance?
> Do recent graduates from college who have no debt start their own business at a higher rate than recent graduates who have debt between $20,000 and $40,000?
> Develop a survey that you could administer using online survey tools such as StatCrunch, surveymonkey.com, or polldaddy.com. Administer the survey. Did the responses accurately reflect the goals of each question? What types of nonsampling error did you e
> By how much does adiposity (a measure of body fat) differ between adult women who maintain a regular sleep schedule versus women whose sleep schedule fluctuates by 90 minutes or more?
> While exercising by climbing stairs, is it better to take one stair, or two stairs, at a time? Researchers identified 30 volunteers who were asked to climb stairs for two different 15-minute intervals taking both one stair and two stairs at a time. Wheth
> Does turmeric (an antioxidant that can be added to foods) help with depression? Researchers randomly assigned 200 adult women who were clinically depressed to two groups. Group 1 had turmeric added to their regular diet for one week; group 2 had no addit
> Does drinking two cups of water before a meal assist with weight loss?
> What proportion of registered voters is in favor of a tax increase to reduce the federal debt?
> What is the typical amount of time 20- to 24-year-old males spend brushing their teeth (each time they brush)?
> Does Marriott Courtyard charge more than Holiday Inn Express for a one-night stay?
> Do adult males who take a single aspirin daily experience a lower rate of heart attacks than adult males who do not take aspirin daily?
> Is the mean IQ of the students in Professor Dang’s statistics class higher than that of the general population, 100?
> Refer to the data in Problem 12. Treat the data as an independent sample. Compute the sample mean difference and standard error of this data. Compute the sample mean difference and standard error treating the data as a dependent sample. What do the resul
> During every election, pollsters conduct exit interviews to help determine which candidate people voted for. During the 2016 presidential election, exit polls under-sampled the number of voters called “Democrat white working-class voters” and over-sample
> It has long been a concern that there is a wage gap between men and women in the United States with some reports suggesting that women only make $0.77 for every dollar earned by a man. Design a study that would allow you to confirm whether a wage gap doe
> John has an online company that sells custom rims for cars. A web-design firm hired by John designed two different web pages to be used to sell his rims online. However, he cannot decide which page to go with, so he decides to collect some data. John hir
> In the fall of 1998, the National Center for Education Statistics (NCES) established a cohort of kindergarten students based on a random sample of all kindergarten students throughout the United States. Objective reading and math assessments were adminis
> As of October 1, 2012, hospitals in the United States with excessive numbers of readmissions based on the Centers for Medicare and Medicaid Services (CMS) data were penalized. Therefore, it is important for hospitals to identify the risk factors associat
> The data below represent the 5-year rate of return (in percent) for a random sample of stocks in financial services and an independent random sample of stocks in health care. Has there been a difference in the rate of return of companies in the Financial
> In today’s “wired” society, students believe that they can multitask. Research suggests that 5% of individuals truly have the ability to multitask. Can students multitask, or do they perform worse while multitasking? In an introductory accounting class,
> Is there a difference in the attitude toward extramarital affairs in the United States versus Canada? Pew Research surveyed a random sample of adults from each country and asked, “Do you personally believe that married people having an affair is morally
> The Pew Research Group asked the following question of individuals who earned in excess of $100,000 per year and those who earned less than $100,000 per year: “Do you believe that it is morally wrong for unwed women to have children?” Of the 1205
> In a study published in the journal Teaching of Psychology, the article “Fudging the Numbers: Distributing Chocolate Influences Student Evaluations of an Undergraduate Course” states that distributing chocolate to students prior to teacher evaluations
> Researchers conducted an experiment in which 695 individuals were shown black and white photographs of individuals running for Congress (either the U.S. Senate or House of Representatives). In each instance, the individuals were exposed to the photogra
> In the federal government’s Current Population Survey, the response rate for 20- to 29-year- olds is 85%; for individuals at least 70 years of age it is 99%. Why do you think this is?
> Do wet suits allow a swimmer to swim faster? Researchers measured the speed (in meters per second) of swimmers both with and without a wetsuit. The results of the study are shown in the table. Conduct the appropriate test to determine whether the data su
> The average major league fastball is 92.0 miles per hour (mph). While there are many other factors other than velocity that are used to judge the quality of this pitch (location and movement, for example), velocity is a major factor in deciding whether a
> Do people tend to spend more money on fast-food when they use a credit card? The following data represent a random sample of credit-card and cash purchases. (a) Draw boxplots of each data set using the same scale. What do the boxplots imply for cash vers
> What is the typical age difference between husband and wife? The following data represent the ages of husbands and wives, based on results from the Current Population Survey. (a) What is the response variable in this study? (b) Is the sampling method dep
> TIMS is an acronym for the Third International Mathematics and Science Study. Kumon promotes a method of studying mathematics that it claims develops mathematical ability. Do data support this claim? In one particular question on the TIMS exam, a random
> Automobile collision insurance is used to pay for any claims made against the driver in the event of an accident. This type of insurance will typically pay to repair any assets that your vehicle damages. (a) Collision claims tend to be skewed right. Why
> The following data represent the measure of a variable before and after a treatment. Does the sample evidence suggest that the treatment is effective in decreasing the value of the response variable? Use the = 0.10 level of significance. Note: Assume t
> (a) Test whether /level of significance for the given sample data. (b) Construct a 95% confidence interval about /
> Explain why using the smaller of / degrees of freedom to determine the critical t instead of Formula (2) is conservative.
> In a MythBusters episode, the question was asked, “Which is better? A four-way stop or a roundabout?” “Better” was determined based on determining the number of vehicles that travel through the four-way stop over a 5-minute interval of time. Suppose the
> The Telephone Consumer Protection Act (TCPA) allows consumers to put themselves on a do-not-call registry. If a number is on the registry, commercial telemarketers are not allowed to call you. Do you believe this has affected the ability of surveyors to
> The Collegiate Learning Assessment Plus (CLA+) is an exam that is meant to assess the intellectual gains made between one’s freshman and senior year of college. The exam, graded on a scale of 400 to 1600, assesses critical thinking, analytical reasoning,
> PayScale reports statistics on colleges and universities. Go to www.pearsonhighered.com/ sullivanstats to obtain the data file 11_3_24 using the file format of your choice for the version of the text you are using. The data contain the four-year cost and
> Professor Stephen Zuro of Joliet Junior College wanted to determine whether an online homework system (meaning students did homework online and received instant feedback with helpful guidance about their answers) improved scores on a final exam. In the f
> Bottles The aluminum bottle, first introduced in 1991 by CCL Container for mainly personal and household items such as lotions, has become popular with beverage manufacturers. Besides being lightweight and requiring less packaging, the aluminum bottle i
> Young children require a lot of time and this time commitment cuts into a parent’s leisure time. A sociologist wanted to estimate the difference in the amount of daily leisure time (in hours) of adults who do not have children under the age of 18 years a
> Do women feel differently from men when it comes to federal tax rates? One question on the Sullivan Statistics Survey II was, “What percent of income do you believe individuals should pay in federal income tax?” Results of the survey may be found at www.
> Stocks may be categorized by sectors. Go to www.pearsonhighered.com/sullivanstats to obtain the data file 11_3_19 using the file format of your choice for the version of the text you are using. The data represent the one- year rate of return (in percent)
> The website touringplans.com records actual wait times (in minutes) for the Pirates of the Caribbean ride and Splash Mountain ride at Walt Disney World. Do the wait times at these two rides differ? (a) To answer this question, a random sample of wait tim
> 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 length of tornadoes in Texas versus Georgi
> Researchers wanted to know whether there was a difference in comprehension among students learning a computer program based on the style of the text. They randomly divided 36 students of similar educational level, age, and so on, into two groups of 18 ea
> Student ID number
> Researchers wanted to determine if carpeted rooms contained more bacteria than uncarpeted rooms. To determine the amount of bacteria in a room, researchers pumped the air from the room over a Petri dish at the rate of 1 cubic foot per minute for eight ca
> Researchers wanted to determine whether the reaction time (in seconds) of males differed from that of females to a go/no go stimulus. The researchers randomly selected 20 females and 15 males to participate in the study. The go/no go stimulus required th
> Ramp metering is a traffic engineering idea that requires cars entering a freeway to stop for a certain period of time before joining the traffic flow. The theory is that ramp metering controls the number of cars on the freeway and the number of cars acc
> Researchers Brian Wansink and Junyong Kim randomly gave 157 moviegoers a free medium (120 grams) or large (250 gram) bucket of popcorn before entering a movie. After the show, the researchers measured how much popcorn the moviegoers consumed. The 77 indi
> Two Dutch researchers conducted a study in which two groups of students were asked to answer 42 questions from Trivial Pursuit. The students in group 1 were asked to spend 5 minutes thinking about what it would mean to be a professor, while the students
> Do business travelers walk at a different pace than leisure travelers? Researcher Seth B. Young measured the walking speed of business and leisure travelers in San Francisco International Airport and Cleveland Hopkins International Airport. His findings
> Do people walk faster in the airport when they are departing (getting on a plane) or when they are arriving (getting off a plane)? Researcher Seth B. Young measured the walking speed of travelers in San Francisco International Airport and Cleveland Hopki
> Testosterone is a steroid in men that affects sex drive, bone, and muscle mass. Researchers wanted to determine the impact of marriage on testosterone levels in males. Source: Stine A. Hogmboe et. al., “Influence of Marital Status on Testosterone Levels—
> A researcher with the Department of Education followed a cohort of students who graduated from high school in 1992, monitoring the progress the students made toward completing a bachelor’s degree. One aspect of his research was to determine whether stude
> Test whether / level of significance for the given sample data.
> Many national polls are based on random-digit dialing (RDD). In this method, a computer randomly generates a phone number in the hopes of reaching an individual at his/her residence. In registration-based sampling (RBS), voter files are used to obtain a
> Test whether /level of significance for the given sample data.
> (a) Test whether /level of significance for the given sample data. (b) Construct a 95% confidence interval about /
> (a) Test whether /level of significance for the given sample data. (b) Construct a 90% confidence interval about /
> (a) Test whether /level of significance for the given sample data. (b) Construct a 95% confidence interval about /
> An experiment was conducted in which 16 ten-month-old babies were asked to watch a climber character attempt to ascend a hill. On two occasions, the baby witnesses the character fail to make the climb. On the third attempt, the baby witnesses either a he
> (a) Determine di = Xi - Yi for each pair of data. (b) Compute / (c) Test if /level of significance. (d) Construct a 99% confidence interval about the population mean difference /
> (a) Determine di = Xi - Yi for each pair of data. (b) Compute / (c) Test if / level of significance. (d) Construct a 95% confidence interval about the population mean difference /
> A researcher wants to show the mean from population 1 is less than the mean from population 2 in matched-pairs data. If the observations from sample 1 are Xi and the observations from sample 2 are / then the null hypothesis is / and the alternative hypot
> A researcher wants to show the mean from population 1 is less than the mean from population 2 in matched-pairs data. If the observations from sample 1 are Xi and the observations from sample 2 are /then the null hypothesis is /and the alternative hypothe
> You are a passenger in a single-propeller-driven aircraft that experiences engine failure in the middle of a flight. The pilot wants to maximize the distance that the plane can glide to increase the likelihood of finding a safe place to land. To accompli
> Consider this question from a recent Gallup poll: Which of the following approaches to solving the nation’s energy problems do you think the U.S. should follow right now—[ROTATED: emphasize production of more oil, gas and coal supplies (or) emphasize mor
> Octane is a measure of how much fuel can be compressed before it spontaneously ignites. Some people believe that higher-octane fuels result in better gas mileage for their cars. To test this claim, a researcher randomly selected 11 individuals (and their
> Chicago has installed cameras at various intersections through the city. The cameras photograph the license plate of any car engaging in a moving violation (such as driving through a red light or failing to stop completely prior to turning on red). Resea
> An automotive researcher wanted to estimate the difference in distance required to come to a complete stop while traveling 40 miles per hour on wet versus dry pavement. Because car type plays a role, the researcher used eight different cars with the same
> To illustrate the effects of driving under the influence (DUI) of alcohol, a police officer brought a DUI simulator to a local high school. Student reaction time in an emergency was measured with unimpaired vision and also while wearing a pair of special
> 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
