11 more than 2 times a number, n, has a result

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?

Asphere has a diameter of 10 in. what is the volume of the sphere?

Write the equation for the parabola that has x− intercepts (−2,0) and (4,0) and y− intercept (0,4).