How many students should you sample?

Question

The SAT scores are distributed with a mean of 1500 any standard deviation of 289. You’re interested in estimating the average SAT score a First your students at your college if you would like to limit the margin of error of your confidence interval to 50 points with an 85% confidence how many students should you sample round up to a whole number of students

Answer 1

MOE = z(s/√n)

50 = 1.44(289/√n)

50 = 416.16/√n

√n = 416.16/50

√n = 8.3232

n = 69.27565824 <-- round up to n=70

Therefore, you should sample 70 students to get a margin of error of 50.

Hope this helped!