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Chapter 1: Problem 15
Classify the variable as qualitative or quantitative. Nation of origin
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The survey design is flawed. (a) Determine whether the flaw is due to the sampling method or the survey itself For flawed surveys, identify the cause of the error (wording of question, nonresponse, and so forth). (b) Suggest a remedy to the problem. To determine public 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 conduct the survey.
Research a survey method used by a company or government branch. Determine the sampling method used, the sample size, the method of collection, and the frame used.
Read the newspaper article and identify (a) the research question the study addresses, (b) the population, (c) the sample, \((d)\) the descriptive statistics, and (e) the inferences of the study. Study: Exercise May Prevent Parkinson's By Kathleen Fackelmann, USA Today Men who engaged in regular, vigorous exercise as teens and young adults drastically cut their risk of developing Parkinson's disease later in life, a study reports Tuesday. As many as 1 million people in the USA, including actor Michael J. Fox, have this progressive neurological disease, which commonly strikes after age \(50 .\) In addition to suggesting that exercise could ward off the disease, the findings also raise the hope that physical activity might help hold the line on brain cell destruction in people who already have it.Robin Elliott, executive director of the Parkinson's Disease Foundation in New York, said the study is promising because there is no cure for Parkinson's. Doctors today have no way to stop or delay the progression of the disease, which affects the brain region that controls movement. Common symptoms of Parkinson's are tremors and a shuffling gait. Researcher Alberto Ascherio of the Harvard School of Public Health and his colleagues studied 48,000 men and 77,000 women who were relatively healthy and middle-aged or older at the study's start. Over the course of the study, 387 people developed the disease. The team did a statistical analysis to look for a link between physical activity and the risk of Parkinson's. Men who said they jogged, played basketball or participated in some other vigorous activity at least twice a week in high school, college and up to age 40 had a \(60 \%\) reduced risk of getting Parkinson's, says the study, which was published today in Neurology. The team found no such protection for women. But the women in this study came of age in the '50s and '60s, an era when young women did not have as many opportunities to participate in sports. Ascherio says. The study had so few female athletes that any protection may have been missed, he says. This study's findings are supported by animal research: Michael Zigmond, a researcher at the University of Pittsburgh and his colleagues have reported that exercise protects rats from developing a Parkinson's-like disease. No one knows for certain whether exercise can prevent or delay the symptoms of Parkinson's in humans. But there is plenty of evidence suggesting that a regular fitness regimen might ward off a host of ailments as diverse as heart disease and Alzheimer's. That leads experts such as Zigmond to recommend a vigorous workout on most days of the week. "We know that exercise is good for you in ways that go beyond any one condition."
A research objective is presented. For each research objective, identify the population and sample in the study. Folate and Hypertension Researcher John P. Forman and co-workers wanted to determine whether or not higher folate intake is associated with a lower risk of hypertension (high blood pressure) in younger women (27 to 44 years of age). To make this determination, they looked at 7,373 cases of hypertension in younger women and found that younger women who consumed at least 1,000 micrograms per day \((\mu \mathrm{g} / \mathrm{d})\) of total folate (dietary plus supplemental) had a decreased risk of hypertension compared with those who consumed less than \(200 \mu \mathrm{g} / \mathrm{d} .\) (Source: "Folate intake and the risk of incident hypertension among US Women," John P. Forman, MD; Eric B. Rimm, ScD; Meir J. Stampfer, MD; Gary C. Curhan, MD, ScD; Journal of the American Medical Association \(293(2005): 320-329)\)
An ad for Crest Whitestrips Premium \(^{\mathrm{TM}}\) claims that the strips will whiten teeth in 7 days and the results will last for 12 months. A researcher who wishes to test this claim studies 20 sets of identical twins. Within each set of twins, one is randomly selected to use Crest Whitestrips Premium in addition to regular brushing and flossing, while the other just brushes and flosses. Whiteness of teeth is measured at the beginning of the study, after 7 days, and every month thereafter for 12 months. (a) What type of experimental design is this? (b) What is the response variable in this experiment? (c) What factor is manipulated? What are the treatments? (d) What is another factor (controlled or uncontrolled) that could affect the response variable? (e) What might be an advantage of using identical twins as subjects in this experiment?
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