SAT scores are distributed with a mean of 1,500 and a standard deviation of 300.

Question

You are interested in estimating the average SAT score of first year students at your college. If you would like to limit the margin of error of your 95% confidence interval to 25 points, how many students should you sample?Make sure to give a whole number answer.

Answer 1

For a mean with population standard deviation (σ) known, you would use this formula:

n= ((Z₉₅ * σ)/Margin of error))² This is just a rearrangement of the margin of error formula to solve for n.

so in this case, n=((1.96)(300)/25)² = 553.19

Always round up your answer for any fractional part, so the whole number answer is 554