Concept explainers
Immunization of Schoolchildren. In the article, “Reasons for Non-uptake of Measles, Mumps, and Rubella Catch Up Immunisation in a Measles Epidemic and Side Effects of the Vaccine” (British Medical Journal, Vol. 310, pp. 1629–1632), R. Roberts et al. discussed a follow-up survey to examine why almost 10,000 children, ages 11–15, whose records showed no previous immunization were not immunized. In the survey, 10 of the 46 schools participating in the immunization campaign were randomly chosen and then the parents of all the nonimmunized children at the 10 selected schools were sent a questionnaire. What type of sampling design was used by these authors in their survey? Explain your answer.
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- Urban Travel Times Population of cities and driving times are related, as shown in the accompanying table, which shows the 1960 population N, in thousands, for several cities, together with the average time T, in minutes, sent by residents driving to work. City Population N Driving time T Los Angeles 6489 16.8 Pittsburgh 1804 12.6 Washington 1808 14.3 Hutchinson 38 6.1 Nashville 347 10.8 Tallahassee 48 7.3 An analysis of these data, along with data from 17 other cities in the United States and Canada, led to a power model of average driving time as a function of population. a Construct a power model of driving time in minutes as a function of population measured in thousands b Is average driving time in Pittsburgh more or less than would be expected from its population? c If you wish to move to a smaller city to reduce your average driving time to work by 25, how much smaller should the city be?arrow_forwardWhat is an experiment?arrow_forward3. What are the effects of repeated exposure to an advertising message? An experiment investigated this question using a random sample of households who regularly watch television. All subjects viewed a 30-minute television program that included ads for a new video camera. Some subjects saw a 30-second commercial, others a 90-second version. The sample commercial was repeated either one, three, or five times during the program. After viewing, all of the subjects answered questions about their recall of the ad, their attitude toward the camera, and their intention to purchase it. For this experiment, four subjects were randomly assigned to each treatment combinations of length of commercial and number of repetitions of the commercial. For this experiment, a) Name the experimental units. b) Name the response variable(s). c) Name the factor(s) or explanatory variable(s) and how many levels each factor has. d) List 3 different possible treatments. e) How many subjects were needed for the…arrow_forward
- According to the 2014 National Survey on Drug Use and Health, 11.4%11.4% of adolescents in the United States had at least one major depressive episode (MDE) in the year prior to be being surveyed. The percentage of MDE among adolescents was approximately three times higher for female adolescents (17.3%17.3% ) than for male adolescents (5.7%5.7% ). (a) Consider the American adolescent population as the sample space of interest. Enter the three percents cited here using probability notation. (Enter your answers rounded to three decimal places.) ?(MDE)=�(MDE)= ?(MDE | female)=�(MDE | female)= ?(MDE | male)=�(MDE | male)= (b) Is MDE independent of sex in the American adolescent population? Select the best explanation. None of the options are correct. No, MDE is not independent of sex in the American adolescent population. Knowing the sex does not change the probability of MDE. No, MDE is not independent of sex in the…arrow_forwardA study prospectively examined whether sleep-disordered breathing was associated with an increased risk of death from any cause in a cohort of 600 adults participating in the Sleep Heart Health Study. Study participants were classified into four groups depending on the extent of their sleep-disordered breathing (none, mild, moderate, or severe). The counts of deaths over the course of the study are reported for each group in the following two-way table. None 40 100 140 Mild 40 100 140 Moderate 20 100 120 Severe 100 Death No Death Total Total 200 400 600 100 200 We want to know whether the study findings give evidence of a significant difference of the number of deaths between the different groups. The test statistic is: MSG F = MSE p-Po z = Fol--Po (0-E) x = E t =arrow_forwardHospital Stays. The U.S. National Center for Health Statistics collects data on length of stay in noninstitutional, short-stay hospitals by sex and age. Results are published in Vital and Health Statistics. Independent random samples of Americans were taken to compare the lengths of stay (in days) for males and females in four age groups (15–24 years, 25–34 years, 35–44 years, and 45–64 years). The data are in the following table. a. the response variable b. the factors c. the levels of each factor d. the number of treatment combinations e. the experimental units f. the number of observations for each treatment combination g. the experimental factors, if any h. the classification factors, if any i. whether the study is a designed experiment or an observational studyarrow_forward
- This question is from the below book, Chapter 15 (Comparing means of more than two groups) , AP 27 Book-Analysis of biological data 2nd Edition Michael C. Whitlock, Dolph Schluter Publisher: W. H. Freeman ISBN: 978193622148 Does adding math to a scientific paper make readers think that it has more value? Erikkson (2012) sent two abstracts of scientific papers to 200 people with postgraduate degrees. For each participant, one of the abstracts was randomly chosen and had a meaningless sentence inserted describing an unrelated. mathematics model, while the other had no mathematical addition. The sentence had no conceptual connection to the subject matter of the abstract; it was just meaningless mathematics in that context. Participants were asked to rate the quality of the research in each abstract on a scale from 1 to 100 and the differences between the scores of their two abstracts -score of the abstract with math minus score of abstract without math-were recorded. Participants were…arrow_forwardIndividuals with strong religious beliefs often turn to their faith to cope with stressful life events. Relying on God's love and caring is referred to as positive religious coping. Andrea Phelps and her colleagues studied the relationship between positive religious coping and the type of care received by terminally ill cancer patients. Most of the patients in the study were Christian. [Source: Phelps, A. et al., "Religious coping and use of intensive life-prolonging care near death in patients with advanced cancer." Journal of the American Medical Association, 301 (2009): 1140-1147.] Suppose another researcher conducts a similar study but uses a sample of patients whose religious traditions are more varied than the patients in the Phelps study. He samples 400 terminally ill patients to see whether their practicing a religion is related to how likely they are to seek intensive life-prolonging care. The following table shows the results of the study. Observed Frequencies Seeks Intensive…arrow_forward
- Functions and Change: A Modeling Approach to Coll...AlgebraISBN:9781337111348Author:Bruce Crauder, Benny Evans, Alan NoellPublisher:Cengage LearningGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillCollege Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage Learning