Members of a bowling league play thousands of combined games over the course of a season. Suppose that the scores of individual
games have a known standard deviation of σ=30 pins. Isla plans on taking a random sample of n games from this population to make a 95% confidence interval for the mean score. She wants the margin of error to be no more than 10 pins. Which of these is the smallest approximate sample size required to obtain the desired margin of error? 9 games
30 games
35 games
43 games
55 games
Think of it logically: A and C are not below sea level so you can cross them out. And B doesn't work because if you decrease -10 by 10 you get -20. So, D is correct.
