Author:
Christine Farr

1. The following are body mass index (BMI) scores measured in 12 patients who are free ofdiabetes and participating in a study of risk factors for obesity. Body mass index ismeasured as the ratio of weight in kilograms to height in meters squared. Generate a 95%confidence interval estimate of the true BMI.2527313326283841243235402. Consider the data in Problem 1. How many subjects would be needed to ensure that a95% confidence interval estimate of BMI had a margin of error not exceeding 2 units?3. The mean BMI in patients free of diabetes was reported as 28.2. The investigatorconducting the study described in Problem 1 hypothesizes that the BMI in patients free ofdiabetes is higher. Based on the data in Problem 1 is there evidence that the BMI issignificantly higher that 28.2? Use a 5% level of significance.4. Peak expiratory flow (PEF) is a measure of a patient’s ability to expel air from the lungs.Patients with asthma or other respiratory conditions often have restricted PEF. The meanPEF for children free of asthma is 306. An investigator wants to test whether childrenwith chronic bronchitis have restricted PEF. A sample of 40 children with chronicbronchitis are studied and their mean PEF is 279 with a standard deviation of 71. Is therestatistical evidence of a lower mean PEF in children with chronic bronchitis? Run theappropriate test at =0.05.5. Consider again the study in Problem 4, a different investigator conducts a second study toinvestigate whether there is a difference in mean PEF in children with chronic bronchitis

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