Equivalent ratio to 2:5

Let the mean of the population be 38 instances of from 6" - 9" hatchings per nest, and let the standard deviation of the mean be 3. what sample mean would have a confidence level of 95% or a 2.5% margin of error?

Iq scores for adults age 20 to 34 years are normally distributed according to n(120, 20). in what range does the middle 68% of people in this group score on the test?

Which one ? is the answer and how to find this answer