Question

QUESTION 1:

We want to estimate the mean change in score µ in the population of all high school seniors. An SRS of 430 high school seniors gained an average of  x¯¯¯x¯ = 22 points in their second attempt at the SAT Mathematics exam. Assume that the change in score has a Normal distribution with standard deviation 48.114.

Find σx¯¯¯σx¯, the standard deviation of the mean change x¯¯¯x¯.   (±±0.001).

Using the 68-95-99.7 Rule (Empirical Rule), give a 99.7% confidence interval for μμ based on this sample.

Confidence interval (±±0.001) is between  and

QUESTION 2:

A class survey in a large class for first-year college students asked, "About how many hours do you study in a typical week?". The mean response of the 431 students was x¯¯¯x¯ = 17 hours. Suppose that we know that the study time follows a Normal distribution with standard deviation 7 hours in the population of all first-year students at this university.

What is the 99% confidence interval (±±0.001) for the population mean?

Confidence interval is from  to  hours.

Answer 1