Body mass index (BMI) is a measure of the body fat based on height and weight. According to the document Dietary Guidelines for Americans, published by the U.S Department of Agriculture and the U.S Department of Health and Human Services, for adults, a BMI of greater than 25 indicates an above healthy weight(i.e., over-weight or obese). Of 750 randomly selected adults whose highest degree is bachelors, 386 have an above healthy weight; and of 500 randomly selected adults with a graduate degree, 237 have an above healthy weight.
(a). Find a 90% confidence interval for the difference interval for the difference of P1-P2 between the proportion of bachelor's degree holders and graduate degree holders.
(b). Find a 95% confidence interval for the difference interval for the difference of P1-P2 between the proportion of bachelors degree holders and graduate degree holders
(c). With reference to part (a) and part (b) which of them gives the best precision and why your choice between them.