For each of the following hypothesis testing scenarios, indicate whether or not the appropriate hypothesis test would be about a difference in two population means. If not, explain why not. Scenario 1: The international polling organization Ipsos reported data from a survey of 2000 randomly selected Canadians who carry debit cards (canadian account habits Survey, july 24, 2006). Participants in this survey were asked what they considered the minimum purchase amount for which it would be acceptable to use a debit card. You would like to determine if there is convincing evidence that the mean minimum purchase amount for which Canadians consider the use of a debit card to be acceptable is less than $10. Scenario 2: Each person in a random sample of 247 male working adults and a random sample of 253 female working adults living in Calgary, Alberta, Canada, was asked how long, in minutes, his or her typical daily commute was (“calgary herald traffic Study,” ipsos, September 17, 2005). You would like to determine if there is convincing evidence that the mean commute times differ for male workers and female workers. Scenario 3: A hotel chain is interested in evaluating reservation processes. Guests can reserve a room using either a telephone system or an online system. Independent random samples of 80 guests who reserved a room by phone and 60 guests who reserved a room online were selected. Of those who reserved by phone, 57 reported that they were satisfied with the reservation process. Of those who reserved online, 50 reported that they were satisfied. You would like to determine if it reasonable to conclude that the proportion who are satisfied is higher for those who reserve a room online.
> What is the distinction between σe and se?
> a. Explain the difference between the line y = a + bx and the line yˆ = a + bx. b. Explain the difference between b and b. c. let x* denote a particular value of the independent variable. Explain the difference between a 1 bx* and a 1 bx*.
> The authors of the paper “decreased brain Volume in Adults with childhood lead exposure” (Public Library of Science Medicine [may 27, 2008]: e112) studied the relationship between childhood environmental lead exposure
> The largest commercial fishing enterprise in the southeastern United States is the harvest of shrimp. In a study described in the paper “long-term trawl monitoring of white Shrimp, litopenaeus setiferus (linnaeus), Stocks within the Ace
> Researchers studying pleasant touch sensations measured the firing frequency (impulses per second) of nerves that were stimulated by a light brushing stroke on the forearm and also recorded the subject’s numerical rating of how pleasant
> Consider a test of hypotheses about, b the population slope in a linear regression model. a. If you reject the null hypothesis, b = 0, what does this mean in terms of a linear relationship between x and y? b. If you fail to reject the null hypothesis,
> Acrylamide is a chemical that is sometimes found in cooked starchy foods and which is thought to increase the risk of certain kinds of cancer. The paper “A Statistical regression model for the estimation of Acrylamide concentrations in
> Do taller adults make more money? The authors of the paper “Stature and Status: height, Ability, and labor market outcomes” (Journal of Political Economics [2008]: 499–532) investigated the association between height and earnings. They used the simple li
> The paper “the effects of Split Keyboard geometry on upper body postures” (ergonomics [2009]: 104–111) describes a study to determine the effects of several keyboard characteristics on typing speed. O
> Consider the accompanying data on x = research and development expenditure (thousands of dollars) and y = growth rate (% per year) for eight different industries. a. Would a simple linear regression model provide useful information for predicting growt
> A nursing student has completed his final project, and is preparing for a meeting with his project advisor. The subject of his project was the relationship between systolic blood pressure (SBP) and body mass index (BMI). The last time he met with his adv
> A journalist is reporting about some research on appropriate amounts of sleep for people 9 to 19 years of age. In that research, a linear regression model is used to describe the relationship between alertness and number of hours of sleep the night befor
> The standard deviation of the errors, se, is an important part of the linear regression model. a. What is the relationship between the value of se and the value of the test statistic in a test of a hypotheses about b? b. What is the relationship betwee
> The production of pups and their survival are the most significant factors contributing to gray wolf population growth. The causes of early pup mortality are unknown and difficult to observe. The pups are concealed within their dens for 3 weeks after bir
> The paper “depression, body mass index, and chronic obstructive pulmonary disease—A holistic Approach” (International Journal of COPD [2016]:239–249) gives data on x = change in Bod
> Consider the accompanying data on x = advertising share and y = market share for a particular brand of soft drink during 10 randomly selected years. a. Construct a scatterplot for these data. Do you think the simple linear regression model would be app
> Hormone replacement therapy (HRT) is thought to increase the risk of breast cancer. The accompanying data on x 5 percent of women using HRT and y 5 breast cancer incidence (cases per 100,000 women) for a region in Germany for 5 years appeared in the pape
> Identify the following relationships as deterministic or probabilistic: a. The relationship between the speed limit and a driver’s speed. b. The relationship between the price in dollars and the price in Euros of an object. c. The relationship between
> Tom and Ray are managers of electronics stores with slightly different pricing strategies for USB drives. In Tom’s store, customers pay the same amount, c, for each USB drive. In Ray’s store, it is a little more exciting. The customer pays an up-front co
> The paper “predicting Yolk height, Yolk width, Albumen length, eggshell weight, egg Shape index, eggshell thickness, egg Surface Area of japanese Quails using Various egg traits as regressors” (International Journal of Poultry Science [2008]: 85–88) sugg
> The flow rate in a device used for air quality measurement depends on the pressure drop x (inches of water) across the device’s filter. Suppose that for x values between 5 and 20, these two variables are related according to the simple linear regression
> Identify the following relationships as deterministic or probabilistic: a. The relationship between height at birth and height at one year of age. b. The relationship between a positive number and its square root. c. The relationship between temperatu
> Suppose that a simple linear regression model is appropriate for describing the relationship between y = house price (in dollars) and x = house size (in square feet) for houses in a large city. The population regression line is y = 23,000 + 47x and σe =
> Let x be the size of a house (in square feet) and y be the amount of natural gas used (therms) during a specified period. Suppose that for a particular community, x and y are related according to the simple linear regression model with = slope of popu
> Identify the following relationships as deterministic or probabilistic: a. The relationship between the length of the sides of a square and its perimeter. b. The relationship between the height and weight of an adult. c. The relationship between SAT s
> Babies born extremely prematurely run the risk of various neurological problems and tend to have lower IQ and verbal ability scores than babies that are not premature. The article “premature babies may recover intelligence, Study Says&a
> Use the information given in the previous exercise to construct and interpret a 95% confidence interval for the difference in mean following distance for Greek taxi drivers while driving with no distractions and while driving and texting.
> The paper referenced in the previous exercise also had the 50 taxi drivers drive in the simulator while sending and receiving text messages. The mean of the 50 sample differences (no distraction – reading text messages) was 1.3 meters and the standard de
> The paper “Driving performance while Using a mobile phone: a Simulation Study of greek professional Drivers” (Transportation Research Part F [2016]: 164–170) describes a study in which 50 Greek male taxi drivers drove in a driving simulator. In the simul
> Can taking chess lessons and playing chess daily improve memory? The online article “the USa junior chess olympics research: Developing memory and Verbal reasoning” (New Horizons for Learning, april 2001; available at
> The paper referenced in the previous exercise also compared the reported heights and weights to actual measured heights and weights for a sample of 1052 female college students selected from eight different universities. The resulting data is summarized
> The authors of the paper “concordance of Self-report and measured height and weight of college Students” (Journal of Nutrition, Education and Behavior [2015]: 94–98) used a pairedsamples t test to reach the conclusion that male college students tend to o
> Use the data given in the previous exercise to complete the following: a. Estimate the mean difference in motion between dominant and nondominant arms for position players using a 95% confidence interval. b. The authors asserted that pitchers have a gr
> The paper “Quantitative assessment of glenohumeral translation in baseball players” (The American Journal of Sports Medicine [2004]: 1711–1715) considered various aspects of shoulder motion for a repr
> Breast feeding sometimes results in a temporary loss of bone mass as calcium is depleted in the mother’s body to provide for milk production. The paper “bone mass is recovered from Lactation to postweaning in adolescen
> Two proposed computer mouse designs were compared by recording wrist extension in degrees for 24 people who each used both mouse designs (“comparative Study of two computer mouse Designs,” cornell human factors Laboratory technical report rp7992). The di
> The article “puppy Love? it’s real, Study Says” (USA ToDAy, april 17, 2015) describes a study into how people communicate with their pets. The conclusion expressed in the title of the article was based on research published in Science (“oxytocin-gaze pos
> The humorous paper “will humans Swim faster or Slower in Syrup?” (American Institute of Chemical Engineers Journal [2004]: 2646–2647) investigated the fluid mechanics of swimming. Twenty swimmers each
> The authors of the paper “Ultrasound techniques applied to body fat measurement in male and female athletes” (Journal of Athletic Training [2009]: 142–147) compared two different methods for measuring
> In Exercise 13.5, a hypothesis test leads to the conclusion that there is not convincing evidence that the mean time to exhaustion for experienced triathletes is greater when they run while listening to motivational music than when they run with no music
> Use the information given in the previous exercise to construct and interpret a 90% confidence interval estimate for the difference in mean MPF at brain location 2 before and after exposure to diesel exhaust.
> In the study described in the paper “exposure to Diesel exhaust induces changes in eeg in human Volunteers” (Particle and Fibre Toxicology [2007]), 10 healthy men were exposed to diesel exhaust for 1 hour. A measure of
> The paper “Less air pollution Leads to rapid reduction of airway inflammation and improved airway function in asthmatic children” (Pediatrics [2009]: 1051–1058) describes a study in which children with mild asthma who live in a pollut
> To determine if chocolate milk is as effective as other carbohydrate replacement drinks, nine male cyclists performed an intense workout followed by a drink and a rest period. At the end of the rest period, each cyclist performed an endurance trial in wh
> The authors of the paper “Statistical methods for assessing agreement between two methods of clinical measurement” (International Journal of Nursing Studies [2010]: 931–936) compared two different ins
> The study described in the previous exercise also measured time to exhaustion for the 11 triathletes on a day when they listened to music that the runners had classified as neutral as compared to motivational. The researchers calculated the difference be
> Many runners believe that listening to music while running enhances their performance. The authors of the paper “effects of Synchronous music on treadmill running among elite triathletes” (Journal of Science and Medici
> For each of the following hypothesis testing scenarios, indicate whether or not the appropriate hypothesis test would be for a difference in two population means. If not, explain why not. Scenario 1: A researcher at the Medical College of Virginia condu
> Descriptions of four studies are given. In each of the studies, the two populations of interest are female students at a particular university and male students at the university. Which of these studies have samples that are independently selected? Study
> Descriptions of four studies are given. In each of the studies, the two populations of interest are the students at a particular university who live on campus and the students who live off campus. Which of these studies have samples that are independentl
> A comprehensive study conducted by the National Institute of Child Health and Human Development tracked more than 1000 children from an early age through elementary school (The New York Times, November 1, 2005). The study concluded that children who spen
> Medical research has shown that repeated wrist extension beyond 20 degrees increases the risk of wrist and hand injuries. Each of 24 students at Cornell University used a proposed new computer mouse design, and while using the mouse, each studentâ&
> A study of fast-food intake is described in the paper “what people buy from fast-food restaurants” (Obesity [2009]:1369–1374). Adult customers at three hamburger chains (McDonald’s, Burger King, and Wendy’s) in New York City were approached as they enter
> Suppose that the researchers who carried out the study described in the previous exercise wanted to estimate the mean following distance with a margin of error of 0.2 meters. Using the given sample standard deviation as a preliminary estimate of the popu
> The authors of the paper “Driving performance while Using a mobile phone: a Simulation Study of greek professional Drivers” (Transportation Research Part F [2016]: 164–170) describe a study to evaluate the effect of mobile phone use by taxi drivers in Gr
> How much money do people spend on graduation gifts? In 2016, the national retail federation (www.nrf.com) surveyed 2511 consumers who reported that they bought one or more graduation gifts in 2016. The sample was selected to be representative of adult Am
> The authors of the paper “Serum Zinc Levels of cord blood: relation to birth weight and gestational period” (Journal of Trace Elements in Medicine and Biology [2015]: 180–183) carried out a study of zinc levels of low-birth-weight babies and normal-birth
> Suppose that a random sample of 50 cans of a particular brand of fruit juice is selected, and the amount of juice (in ounces) in each of the cans is determined. Let µ denote the mean amount of juice for the population of all cans of this brand. Suppose t
> The article “the association between television Viewing and irregular Sleep Schedules among children Less than 3 Years of age” (Pediatrics [2005]: 851–856) reported the accompanying 95% confidence int
> Let x represent the time (in minutes) that it takes a fifth grade student to read a certain passage. Suppose that the mean and standard deviation of the x distribution are µ = 2 minutes and σ = 0.8 minutes, respectively. a. If x is the sample mean time
> Suppose that college students with a checking account typically write relatively few checks in any given month, whereas people who are not college students typically write many more checks during a month. Suppose that 50% of a bank’s accounts are held by
> Major League Baseball (MLB) includes two groups of teams, in “leagues.” There are 15 teams in each of the American League (AL) and the National League (NL). Since 1997, teams in each of the leagues play teams from the
> Exercise 12.44 asks whether a representative sample of Big Mac prices (after conversion to U.S. dollars) from countries in Europe provides evidence that the mean European price is less than the reported U.S. price of $5.04. Here are the data: a. What cha
> Researchers studied ergometer (rowing machine) time (in seconds) for international male competitors in the 2007 World Junior Rowing Championships. They found that the mean time to row 2000 meters on an ergometer for the population of international sculls
> Consumer Reports provides ratings for televisions, including energy cost per year (in dollars) (www.consumerreports.org/products/lcd-led-oled-tvs/ratings-overview/, retrieved December 23, 2016). Energy cost data for a sample of 13 small televisions (29-i
> Teams in the National Football League (NFL) are given a “bye” during one week of the season, when they can rest and not play a game. This may provide an advantage for the team in the next game they play after a bye. I
> Example 12.12 provided the following 21-time discrimination scores for male smokers who had abstained from smoking for 24 hours. a. What characteristic of the sample size indicates that the methods based on the t distribution may not be appropriate? b.
> The dodo was a species of flightless bird that lived on the island of Mauritius in the Indian Ocean. The first record of human interaction with the dodo occurred in 1598, and within 100 years the dodo was extinct due to hunting by humans and other newly
> Consumer Reports published the following gas mileage values (Overall MPG) for a sample of electric or plugin hybrid car models (www.consumerreports.org/cro/cars /new-cars/hybrids-evs/ratings-reliability/ratings-overview. htm, retrieved December 23, 2016)
> A hot tub manufacturer advertises that a water temperature of 100°F can be achieved in 15 minutes or less. A random sample of 25 tubs is selected, and the time necessary to achieve a 100°F temperature is determined for each tub. The sample mean time and
> A student organization uses the proceeds from a soft drink vending machine to finance its activities. The price per can was $0.75 for a long time, and the mean daily revenue during that period was $75.00. The price was recently increased to $1.00 per can
> An automobile manufacturer decides to carry out a fuel efficiency test to determine if it can advertise that one of its models achieves 30 mpg (miles per gallon). Six people each drive a car from Phoenix to Los Angeles. The resulting fuel efficiencies (i
> USA TODAY (October 14, 2016) reported that Americans spend 4.1 hours per weekday checking work e-mail. This was an estimate based on a survey of 1004 white-collar workers in the United States. a. Suppose that you would like to know if there is evidence
> People in a random sample of 236 students enrolled at a liberal arts college were asked questions about how much sleep they get each night (“alcohol consumption, Sleep, and academic performance among college Students,” Journal of Studies on Alcohol and D
> The authors of the paper “mean platelet Volume could be possible biomarker in early Diagnosis and monitoring of gastric cancer” (Platelets [2014]: 592–594) wondered if mean platelet volume (MPV) might be a way to distinguish patients with gastric cancer
> The eating habits of n = 12 bats were examined in the article “foraging behavior of the indian false Vampire bat” (Biotropica [1991]: 63–67). These bats consume insects and frogs. For these 12 bats, the mean time to consume a frog was x = 21.9 minutes. S
> Give as much information as you can about the P-value of a t test in each of the following situations: a. Two-tailed test, n = 16, t = 1.6 b. Upper-tailed test, n = 14, t = 3.2 c. Lower-tailed test, n = 20, t = -5.1 d. Two-tailed test, n = 16, t = 6.
> Many consumers pay careful attention to stated nutritional contents on packaged foods when making purchases, so it is important that the information on packages be accurate. Suppose that a random sample of n = 12 frozen dinners of a certain type was sele
> The authors of the paper “changes in Quantity, Spending, and nutritional characteristics of adult, adolescent and child Urban corner Store purchases after an environmental intervention” (Preventative Medicine [2015]: 81–85) wondered if increasing the ava
> The report “majoring in money: how american college Students manage their finances” (Salliemae, 2016, www.news/salliemae.com, retrieved December 24, 2106) includes data from a survey of college students. Each person in a representative sample of 793 coll
> The report “2016 Salary Survey executive Summary” (national association of colleges and employers, www.naceweb.org/uploadedfiles/files/2016/publications/executivesummary/2016-nace-salary-survey-fall-executive-summary. pdf, retrieved December 24, 2016) s
> Give as much information as you can about the P-value of a t test in each of the following situations: a. Two-tailed test, df = 9, t = 0.73 b. Upper-tailed test, df = 10, t = 0.5 c. Lower-tailed test, n = 20, t = -2.1 d. Two-tailed test, n = 40, t =
> The paper titled “music for pain relief” (The Cochrane Database of Systematic Reviews, april 19, 2006) concluded, based on a review of 51 studies of the effect of music on pain intensity, that “Listening to music reduces pain intensity levels … However,
> In a study of media use, each person in a large representative sample of male Canadian high school students was asked how much time they spent playing video or computer games (in minutes per day). The sample mean was 123.4 minutes and the sample standard
> The Economist collects data each year on the price of a Big Mac in various countries around the world. A sample of McDonald’s restaurants in Europe in July 2016 resulted in the following Big Mac prices (after conversion to U.S. dollars)
> The paper referenced in the previous exercise also states that the known mean resting heart rate for boys in this age group is 66 bpm. a. Is there convincing evidence that the mean heart rate after Wii Bowling for 15 minutes is higher than the known mea
> The paper “playing active Video games increases energy expenditure in children” (Pediatrics [2009]: 534–539) describes a study of the possible cardiovascular benefits of active video games. Mean heart rate for healthy boys ages 10 to 13 after walking on
> Give as much information as you can about the P-value of a t test in each of the following situations. (Hint: See discussion on page 594.) a. Upper-tailed test, df = 8, t = 2.0 b. Lower-tailed test, df = 10, t = -2.4 c. Lower-tailed test, n = 22, t =
> The article “americans’ big Debt burden growing, not evenly Distributed” (www.gallup.com, retrieved December 14, 2016) reported that for a representative sample of Americans born between 1965 and 1971 (known as Generation X), the sample mean number of cr
> Use the information given in the previous exercise to construct a 95% confidence interval for the mean number of partners on a mating flight for queen honeybees. For purposes of this exercise, assume these 30 queen honeybees are representative of the pop
> The paper “the curious promiscuity of Queen honey bees (Apis mellifera): evolutionary and behavioral mechanisms” (Annals of Zoology [2001]:255–265) describes a study of the mating behavior of queen honeybees. The following quote is from the paper: Queen
> Five students visiting the student health center for a free dental examination during National Dental Hygiene Month were asked how many months had passed since their last visit to a dentist. Their responses were: Assuming that these five students can be
> Consumer Reports gave the following mileage ratings (in miles per gallon) for seven midsize hybrid 2016 model cars (www.consumerreports.org/cro/cars/new-cars /hybrids-evs/ratings-reliability/ratings-overview.htm, retrieved December 21, 2016). Is it reaso
> The formula used to calculate a confidence interval for the mean of a normal population when n is small is /What is the appropriate t critical value for each of the following confidence levels and sample sizes? a. 95% confidence, n = 15 b. 99% confiden
> What percentage of the time will a variable that has a t distribution with the specified degrees of freedom fall in the indicated region? a. 5 df, between -2.02 and 2.02 b. 14 df, between -2.98 and 2.98 c. 22 df, outside the interval from -1.72 to 1.7
> Because of safety considerations, in May 2003, the Federal Aviation Administration (FAA) changed its guidelines for how small commuter airlines must estimate passenger weights. Under the old rule, airlines used 180 pounds as a typical passenger weight (i
> A manufacturer of college textbooks is interested in estimating the strength of the bindings produced by a particular binding machine. Strength can be measured by recording the force required to pull the pages of a book from its binding. If this force is
> Acrylic bone cement is sometimes used in hip and knee replacements to secure an artificial joint in place. The force required to break an acrylic bone cement bond was measured for six specimens, and the resulting mean and standard deviation were 306.09 N
> USA TODAY reported that the average amount of money spent on coffee drinks each month is $78.00 (USA Snapshot, November 4, 2016). a. Suppose that this estimate was based on a representative sample of 20 adult Americans. Would you recommend using the one
> Samples of two different models of cars were selected, and the actual speed for each car was determined when the speedometer registered 50 mph. The resulting 95% confidence intervals for mean actual speed were (51.3, 52.7) for model 1 and (49.4, 50.6) fo
