The Diabetes Prevention Study was a randomized study conducted in Finland in which middle-aged participants (
Table 8.30 Mean weight change by treatment group among people with IGT in the Diabetes Prevention Study
*Follow-up weight – baseline weight.
For the purposes of this problem, for any degrees of freedom (d) ≥ 200, assume that td ≅ N (0, 1) distribution.
What test can be used to assess mean changes in weight in the intervention group?
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Fundamentals of Biostatistics
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- A sociologist wants to investigate the question, "Is there a relationship between texting during class and grade-point-average (GPA) among high school seniors in a large district?" Which study design is most appropriate? Before the semester starts, randomly select 40 seniors from each high school who do not text during class. Assign 20 to the texting treatment group (text three or more times during every class meeting) and 20 to the control group (no texting during class). At the end of the semester, obtain each student’s GPA from the appropriate admissions and records office. Compare the GPA of students who routinely text during class to the GPA of students who do not text during class. Before the semester starts, randomly select 40 seniors from each high school who do not text during class. Assign 20 to the texting treatment group (text three or more times during every class meeting) and 20 to the control group (no texting during class). At the end of the semester,…arrow_forwardIn a study of 301 Hispanic women living in San Antonia, Texas, one variable of interest was the percentage of subjects with impaired fasting glucose (IFG). IFG refers to a metabolic stage intermediate between normal glucose homeostasis and diabetes. In the study, 24 women were classified in the IFG stage. The article cites population estimates for IFG among Hispanic women in Texas as 6.3%. Is there sufficient evidence to indicate the population of Hispanic women in San Antonio has a prevalence of IFG higher than 6.3%? Use 95% confidence level and the p -value method to form your conclusion. The computed z score was 1.193. Find the p-value.arrow_forwardIn a study of 301 Hispanic women living in San Antonia, Texas, one variable of interest was the percentage of subjects with impaired fasting glucose (IFG). IFG refers to a metabolic stage intermediate between normal glucose homeostasis and diabetes. In the study, 24 women were classified in the IFG stage. The article cites population estimates for IFG among Hispanic women in Texas as 6.3%. Is there sufficient evidence to indicate the population of Hispanic women in San Antonio has a prevalence of IFG higher than 6.3%? Use 95% confidence level and the p -value method to form your conclusion. Answer the problem in a complete sentence.arrow_forward
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- A particular paper described a study of children who were underweight or normal weight at age 2. Children in the sample were classified according to the number of sweet drinks consumed per day and whether or not the child was overweight one year after the study began. Is there evidence of an association between whether or not children are overweight after one year and the number of sweet drinks consumed? Assume that it is reasonable to regard the sample of children in this study as representative of 2 to 3 years old children and then test the appropriate hypotheses using a .05 significance level. (Round your answer to two decimal places.) Number of Sweet Overweight? Drinks Consumed per Day Yes No 22 930 1 73 2071 2 56 1681 3 or More 102 3389 x2 = | P-value interval Op< 0.001 O 0.001 s p < 0.01 O 0.01 sp < 0.05 O 0.05 sp < 0.10 Op2 0.10 There is --Select--- v to conclude that there is an association between whether or not children are overweight after one year and the number of sweet…arrow_forwardPassive exposure to environmental tobacco smoke has been associated with growth suppression and an increased frequency of respiratory tract infections in normal children. Is this association more pronounced in children with cystic fibrosis? To answer this question, 43 children (18 girls and 25 boys) attending a 2-week summer camp for cystic fibrosis patients were studied (New England Journal of Medicine, Sept. 20, 1990). Among several variables measured were the child's weight percentile (y) and the number of cigarettes smoked per day in the child's home (x). a. For the 18 girls, the coefficient of correlation between y and x was reported as r = –.50. Interpret - this result. b. Refer to part a. The p-value for testing Ho: p = 0 against H;: p # 0 was reported as p = .03. n Interpret this result. c. For the 25 boys, the coefficient of correlation between y and x was reported asr = -.12. Interpret %3D %3D this result. d. Refer to part c. The p-value for testing Ho: p = 0 against Ha: p #…arrow_forwardA researcher surveyed 500 people. She found that the individuals who took some form of over the counter sleep aid (i.e. ZZZQuil) were able to fall asleep in a shorter period of time and stay asleep for longer periods than the individuals who did not. a) Was this study observational or experimental? Why?b) What was the explanatory variable? What was the response variable?arrow_forward
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