You are planning on taking an SRS of 100 people from a population that has a mean () age of 40 years and standard deviation () of 15 years. The distribution is slightly skewed, but according to the Central Limit Theorem the distribution of all sample means is approximately normal. Using the distribution of the sample means, according to the 68-95-99.7 rule, how far away are approximately 95% of all of the possible sample means ('s) from 40 years? (This is the MIDDLE 95%).

95% of the possible sample means are within +/- (plus or minus) years from 40 years.

(Hint: how many standard deviations do you need to go from the center to get 95%? Don't forget this is all about the SAMPLE MEANS, not the original population)