Question 407358
This answer left one thing out of the formula for answer A. Though, it is probably too late to be helpful to you now, it may be to someone else. The formula for A would be (70.3 - 71.7)/(3.95/41) and solve from there. When using a sample, the formula is the same as was given to find a z score for a whole population, except you have to divide the standard deviation in the denominator by n(the number in the sample).