Question

Problem 9. Chicken Soup The overall U.S. prevalence rate of flu during the month of February 2016 was 9%. During the same time period, the Louisiana Dept of Health conducted a survey to estimate flu prevalence in Louisiana. Of the 400 survey respondents, 50 reported having the flu during the month of February 2016 resulting in an observed prevalence rate (or proportion of individuals with the flu) of 12.5%. Based on the results of the survey, construct a 95% CI forp, the population prevalence (proportion of population) of flu in LA during February 2016. Problem 10. Through Rain, Sleet and Snow It is known that the mean weight of all items sent through LSUHSC's campus mail system is 30 grams. A random sample of 25 campus mail items received by the School of Public Health had an average weight of 36 grams with a sample standard deviation of 16 grams. Construct the appropriate two-sided CI for the mean weight of mail received by the School of Public Health.

please help me.

Answer 1

9. The confidence interval for a proportion is given as:

pty p(1-P)

We have,

p=0.125, n = 400

Z is the corresponding z-value for 95% confidence interval. This can be looked up from a standard normal table as 1.96

The confidence interval is now given as:

10.125(1-0.125) 0.125 +1.964/ | 400
=
0.125 +0.0324
= [0.0926, 0.1574]

In percentages, the confidence interval is [9.26%, 15.74%]