Question

SUPP 5.2

In a sample of 1200 patients, the average number of days from exposure to diagnosis of a disease is 19.0 days. We know (unrealistically) that the population standard deviation is 5.5 days= sigma x

1. Find a 95% CI for the average days from exposure to diagnosis.

2. Can we say that 95% of the values (days from exposure to diagnosis) for the sample are in the CI you computed in a)? Can we say that 95% of the values (days from exposure to diagnosis) for the population are in the CI you computed in a)? Explain briefly.

3. Do the values for “days from exposure to diagnosis” need to be normally distributed for your part a) to be valid? Explain briefly.

4. Briefly explain the difference between  sigma x and sigma xbar

Answer 1