The Body Mass Index (BMI) is a value calculated based on theweight and the height of an individual. In a small European city, asurvey was conducted one year ago to review the BMI of thecitizens. In the sample with 200 citizens, the mean BMI was 23.3kg/m2 and standard deviation was 1.5 kg/m2 . It is reasonable toassume the BMI distribution is a normal distribution.
(a) Find the point estimate of the population mean BMI one yearago.
(b) Calculate the sampling error at 90% confidence.
(c) Construct a 90% confidence interval estimate of thepopulation mean BMI one year ago. This city launched a healthyexercise program to reduce citizen’s BMI after last year’s survey.Suppose the program effectively reduces the BMI of each citizen by2.5%.
(d) Construct a 98% confidence interval estimate of thepopulation mean BMI after the healthy exercise program. (Hint: findthe updated sample mean and sample standard deviation of the BMI ofthe sample with 200 citizens selected last year)
