The report referenced in the previous exercise also gave data for representative samples of 250 adults in Canada and 250 adults in England. The sample mean amount of sleep on a work night was 423 minutes for the Canada sample and 409 minutes for the England sample. Suppose that the sample standard deviations were 35 minutes for the Canada sample and 42 minutes for the England sample. a. Construct and interpret a 95% confidence interval estimate of the difference in the mean amount of sleep on a work night for adults in Canada and adults in England. b. Based on the confidence interval from Part (a), would you conclude that there is evidence of a difference in the mean amount of sleep on a work night for the two countries? Explain why or why not.
> Studies have been conducted to evaluate the effectiveness of psilocybin mushrooms on improving the quality of life for patients with cancer (“a Dose of a hallucinogen from a ‘magic mushroom,’ and then
> Use the information given in the previous exercise to construct a 95% bootstrap confidence interval to estimate the difference in mean average working heart rates for the driver in teams of two firefighters and the driver in teams of from three to five f
> The Sheboygan (Wisconsin) Fire Department received a report on the potential effects of reductions in the number of firefighters it employs (“Study of fire Department causes controversy,” USA ToDAy NETWoRK-Wisconsin, D
> Use the information given in the previous exercise to calculate a 95% bootstrap confidence interval to estimate the mean difference in movement, OFF – CL. Interpret the interval in context. You can use make use of the Shiny apps in the collection at stat
> New “closed loop” (CL) devices have been developed to help to suppress overactive brain activity in patients with conditions such as Parkinson’s disease and epilepsy (“conceptualizat
> The online article “Death metal in the operating room” (www.npr.org, December 24, 2009) describes an experiment investigating the effect of playing music during surgery. One conclusion drawn from this experiment was that doctors listening to music that c
> The paper “Supervised exercise Versus non-Supervised exercise for reducing weight in obese adults” (The Journal of Sports Medicine and Physical Fitness [2009]: 85–90) describes an experiment in which
> The paper “the effect of multitasking on the grade performance of business Students” (Research in Higher Education Journal [2010]: 1–10) describes an experiment in which 62 undergraduate business stud
> The paper “Supervised exercise Versus nonSupervised exercise for reducing weight in obese adults” (The Journal of Sports Medicine and Physical Fitness [2009]: 85–90) describes an experiment in which p
> The paper “the effect of multitasking on the grade performance of business Students” (Research in Higher Education Journal [2010]: 1–10) describes an experiment in which 62 undergraduate business stud
> The article referenced in the previous exercise also described an experiment in which students at Columbia Business School were randomly assigned to one of two groups. Students in one group were shown a coffee mug and asked how much they would pay for th
> The article “why we fall for this” (AARP Magazine, may/June 2011) describes an experiment investigating the effect of money on emotions. In this experiment, students at University of Minnesota were randomly assigned to one of two groups. One group counte
> The article “Dieters Should Use a bigger fork” (Food Network Magazine, January/February 2012) described an experiment conducted by researchers at the University of Utah. The article reported that when people were randomly assigned to either eat with a sm
> The authors of the paper “the empowering (Super) heroine? the effects of Sexualized female characters in Superhero films on women” (Sex Roles [2015]: 211–220) were interested in the effect on female viewers of watching movies in which female heroines wer
> The paper “Does the color of the mug influence the taste of the coffee?” (Flavour [2014]: 1–7) describes an experiment in which subjects were assigned at random to one of two treatment groups. The 12 people in one group were served coffee in a white mug
> The paper “if it’s hard to read, it’s hard to Do” (Psychological Science [2008]: 986–988) described an interesting study of how people perceive the effort required
> The accompanying data on food intake (in Kcal) for 15 men on the day following two nights of only 4 hours of sleep each night and for 15 men on the day following two nights of 8 hours of sleep each night is consistent with summary quantities in the paper
> The paper “effects of caffeine on repeated Sprint ability, reactive agility time, Sleep and next Day performance” (Journal of Sports Medicine and Physical Fitness [2010]: 455–464) describes an experiment in which male athlete volunteers who were consider
> The paper “Supervised exercise Versus non-Supervised exercise for reducing weight in obese adults” (The Journal of Sports Medicine and Physical Fitness [2009]: 85–90) describes an experiment in which participants were randomly assigned either to a superv
> Use the information given in the previous exercise to complete the following: a. Construct and interpret 95% confidence intervals for the difference in mean pain intensity between the two treatments at 14 days and at 1 month after treatment. b. Based o
> Is injecting medical cement effective in reducing pain for people who have suffered fractured vertebrae? The paper “a randomized trial of Vertebroplasty for osteoporotic Spinal fractures” (New England Journal of Medici
> The accompanying data on food intake (in Kcal) for 15 men on the day following two nights of only 4 hours of sleep each night and for 15 men on the day following two nights of 8 hours of sleep each night are consistent with summary quantities in the pape
> Use the information in the previous exercise to estimate the difference in the mean number of correct answers for the two different methods. Use a 95% confidence level, and be sure to interpret the interval in the context of the experiment.
> Can moving their hands help children learn math? This question was investigated in the paper “gesturing gives children new ideas about math” (Psychological Science [2009]: 267–272). Eighty-five childr
> The article “an alternative Vote: applying Science to the teaching of Science” (The Economist, may 12, 2011) describes an experiment conducted at the University of British Columbia. A total of 850 engineering students enrolled in a physics course partici
> The paper “Short-term Sleep Loss Decreases physical activity Under free-Living conditions but Does not increase food intake Under time-Deprived Laboratory conditions in healthy men” (American Journal of Clinical Nutrition [2009]: 1476–1483) describes an
> The paper “the effect of multitasking on the grade performance of business Students” (Research in Higher Education Journal [2010]: 1–10) describes an experiment in which 62 undergraduate business students were randomly assigned to one of two experimental
> Research has shown that for baseball players, good hip range of motion results in improved performance and decreased body stress. The article “functional hip characteristics of baseball pitchers and position players” (The American Journal of Sports Medic
> Are girls less inclined to enroll in science courses than boys? One study (“intentions of Young Students to enroll in Science courses in the future: an examination of gender Differences” (Science Education [1999]: 55&a
> Wayne Gretzky was one of ice hockey’s most prolific scorers when he played for the Edmonton Oilers. During his last season with the Oilers, Gretzky played in 41 games and missed 17 games due to injury. The article “the
> A researcher at the Medical College of Virginia conducted a study of 60 randomly selected male soccer players and concluded that players who frequently “head” the ball have a lower mean IQ than those who do not (USA To
> A newspaper story headline reads “gender plays part in monkeys’ toy choices, research finds—Like humans, male monkeys choose balls and cars, while females prefer Dolls and pots” (Kni
> Use the information given in the previous exercise to estimate the difference in mean GPA for students at the University of Central Florida who are employed and students who are not employed. Use a 90% confidence level to produce your estimate.
> In a study of the effect of college student employment on academic performance, the following summary statistics for GPA were reported for a sample of students who worked and for a sample of students who did not work (University of Central Florida Underg
> In a study of malpractice claims where a settlement had been reached, two random samples were selected: a random sample of 515 closed malpractice claims that were found not to involve medical errors and a random sample of 889 claims that were found to in
> Use the information given in the previous exercise to construct and interpret a 95% confidence interval estimate of the difference in mean brain volume for children with and without ADHD.
> Do children diagnosed with attention deficit/ hyperactivity disorder (ADHD) have smaller brains than children without this condition? This question was the topic of a research study described in the paper “Developmental trajectories of
> Use the information given in the previous exercise to construct and interpret a 95% confidence interval estimate of the difference in mean daily calorie intake for teens who do eat fast food on a typical day and those who do not.
> What impact does fast-food consumption have on various dietary and health characteristics? The article “effects of fast-food consumption on energy intake and Diet Quality among children in a national household Study” (
> Research has shown that, for baseball players, good hip range of motion results in improved performance and decreased body stress. The article “functional hip characteristics of baseball pitchers and position players” (The American Journal of Sports Medi
> The article “plugged in, but tuned out” (USA ToDAy, January 20, 2010) summarizes data from two surveys of kids age 8 to 18. One survey was conducted in 1999 and the other was conducted in 2009. Data on number of hours
> Reduced heart rate variability (HRV) is known to be a predictor of mortality after a heart attack. One measure of HRV is the average normal-to-normal beat interval (in milliseconds) for a 24-hour time period. Twenty-two heart attack patients who were dog
> Internet addiction has been described as excessive and uncontrolled Internet use. The authors of the paper “gender Difference in the relationship between internet addiction and Depression” (Computers in Human Behavior [2016]: 463–470) used a score design
> The authors of the paper “influence of biofeedback weight bearing training in Sit to Stand to Sit and the Limits of Stability on Stroke patients” (The Journal of Physical Therapy Science [2016]: 3011–
> Use the information in the previous exercise to answer the following questions. a. Construct a 95% confidence interval estimate of the difference in mean time spent on Facebook for male college students and female college students in Southern California
> The paper “facebook Use and academic performance among college Students: a mixed-methods Study with a multiethnic Sample” (Computers in Human Behavior [2015]: 265–272) describes a survey of a sample of 66 male students and a sample of 195 female students
> The paper “pathological Video-game Use among Youth ages 8 to 18: a national Study” (Psychological Science [2009]: 594–705) included the information in the accompanying table about video game playing t
> The paper referenced in the Preview Example of this chapter (“mood food: chocolate and Depressive Symptoms in a cross-Sectional analysis,” Archives of Internal Medicine [2010]: 699–703) describes a study that investigated the relationship between depress
> Do female college students spend more time watching TV than male college students? This was one of the questions investigated by the authors of the paper “an ecological momentary assessment of the physical activity and Sedentary behaviour patterns of Uni
> The National Sleep Foundation surveyed representative samples of adults in six different countries to ask questions about sleeping habits (“2013 international bedroom poll Summary of findings,” www.sleepfoundation.org/sites /default/files/rpt495a.pdf, re
> The article “genetic tweak turns promiscuous animals into Loyal mates” (Los Angeles Times, june 17, 2004) summarizes a research study that appeared in the June 2004 issue of Nature. In this study, 11 male meadow voles
> Use the information in the previous exercise to answer the following questions. a. Construct a 90% confidence interval estimate of the difference in mean Flesch reading ease score for healthrelated pages on Wikipedia and health-related pages on WebMD.
> Many people now turn to the Internet to get information on health-related topics. The paper “an examination of health, medical and nutritional information on the internet: a comparative study of wikipedia, webmD and the mayo clinic websites” (The Interna
> Example 13.5 looked at a study comparing students who use Facebook and students who do not use Facebook (“facebook and academic performance,” Computers in Human Behavior [2010]: 1237–1245). In addition to asking the students in the samples about GPA, eac
> In a study of memory recall, 8 students from a large psychology class were selected at random and given 10 minutes to memorize a list of 20 nonsense words. Each was asked to list as many of the words as he or she could remember both 1 hour and 24 hours l
> Babies born extremely prematurely run the risk of various neurological problems and tend to have lower IQ and verbal ability scores than babies who are not premature. The article “premature babies may recover intelligence, Study Says&ac
> 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 adolesce
> In a study of memory recall, 8 students from a large psychology class were selected at random and given 10Â minutes to memorize a list of 20 nonsense words. Each was asked to list as many of the words as he or she could remember both 1 hour an
> Suppose you are given the computer output shown. You want to test the hypothesis, b = 1.0. Describe how you would use the computer output to test this hypothesis. Linear Fit y = 5.6452776 + 0.9797401*x Summary of Fit RSquare RSqureAdj Root Mean Squa
> Researchers in Hawaii have recently documented a large increase in the prevalence of a bird parasite known as chewing lice (“explosive increase in ectoparasites in hawaiian forest birds,” The Journal of Parasitology [2
> Ruffed grouse are a species of birds that nest on the ground. Because of this, chick survival at night in the first few weeks of life depends on avoiding predators. Biologists have theorized that protection from predators might be supplied by the mother
> There are 4 basic assumptions necessary for making inferences about b, the slope of the population regression line. a. What are the four assumptions? b. Which assumptions can be checked using sample data? c. What statistics or graphs would be used to
> Theropods were carnivorous dinosaurs, characterized by short forelimbs, living in the Jurassic and Cretaceous periods. (Tyrannosaurus rex is classified as a Theropod.) What scientists know about therapods is based on studying incomplete skeletal remains.
> The SAT and ACT exams are often used to predict a student’s first-term college grade point average (GPA). Different formulas are used for different colleges and majors. Suppose that a student is applying to State U with an intended major in civil enginee
> In the context of the simple linear regression model, explain the difference between a and a. Between b and b. Between σe and se.
> Explain what distinguishes a deterministic model from a probabilistic model.
> The authors of the article “Age, Spacing and Growth Rate of Tamarix as an Indication of Lake Boundary Fluctuations at Sebkhet Kelbia, Tunisia” ( Journal of Arid Environments [1982]: 43–5 1) used a sim
> 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 bi
> The sand scorpion is a predator that always hunts from a motionless resting position outside its own burrow. When prey appears on the horizon, within say 20 cm, the scorpion assumes an alert posture; it determines the angular position of the prey, makes
> Models of climate change predict that global temperatures and precipitation will increase in the next 100 years, with the largest changes occurring during winter in northern latitudes. Researchers recently gathered data on the potential effects of climat
> Carbon acrosols have been identified as a contributing factor in a number of air quality problems. In a chemical analysis of diesel engine exhaust, x = mass (mg/cm2) and y = elemental carbon (mg/cm2) were recorded ("comparison of Solvent extraction and t
> Investigators in northern Alaska periodically monitored radio collared wolves in 25 wolf packs over 4 years, keeping track of the packs’ home ranges (“population dynamics and harvest characteristics of wolves in the ce
> The accompanying scatterplot, based on 34 sediment samples with x = sediment depth (cm) and y = oil and grease content (mg/kg), appeared in the article “mined land reclamation using polluted urban navigable waterway Sedimentsâ
> Exercise 15.21 gave data on x = nerve firing frequency and y = pleasantness rating when nerves were stimulated by a light brushing stoke on the forearm. The x values and the corresponding residuals from a simple linear regression are as follows: a. Con
> In the study described in Exercise 15.31, the effect of latitude on mean clutch size was investigated. Data from various locations in Florida, Georgia, Alabama, and Mississippi on y = mean clutch size and x = latitude were measured. The scatterplot, stan
> Models of climate change predict that global temperatures and precipitation will increase in the next 100 years, with the largest changes occurring during winter in northern latitudes. Researchers gathered data on the potential effects of climate change
> The article “Vital dimensions in Volume perception: can the eye fool the Stomach?” (Journal of Marketing Research [1999]: 313– 326) gave the accompanying data on the dimensions (in cm) of the containe
> Carbon aerosols have been identified as a contributing factor in a number of air quality problems. In a chemical analysis of diesel engine exhaust, x = mass (mg/cm2) and y = elemental carbon (mg/cm2) were recorded (“comparison of Solven
> The clutch size (number of eggs laid) for turtles is known to be influenced by body size, latitude, and average environmental temperature. Researchers gathered data on Gopher tortoises in Okeeheelee County Park in Florida to further understand the factor
> The following graphs are based on data from an experiment to assess the effects of logging on a squirrel population in British Columbia (“effects of logging pattern and intensity on Squirrel demography,” The Journal of
> Suppose you are given the computer output shown. You are interested in testing the null hypothesis b = 1.0 versus an alternative hypothesis of b > 1.0. Describe how you would use the given computer output to test these hypotheses. Linear Fit y =
> In anthropological studies, an important characteristic of fossils is cranial capacity. Frequently skulls are at least partially decomposed, so it is necessary to use other characteristics to obtain information about capacity (in cm3). One measure that h
> The paper referenced in Exercise 15.11 (“depression, body mass index, and chronic obstructive pulmonary disease—A holistic Approach,” International Journal of COPD [2016]:239–249) ga
> The accompanying data are a subset of data from the report “great jobs, great lives” (gallup-purdue index 2015 report, www.gallup.com/reports/197144/gallup-purdue -index-report-2015.aspx, retrieved may 27, 2017). The v
> 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
