A junior at a large high school wants to estimate the amount of time it takes to log in to a school computer. He randomly selects 35 students and records the amount of time it takes to log in. The junior constructs a 95%
confidence interval for the true mean amount of time it takes to log in to a school computer. Which of the following
would decrease the margin of error?
O using a sample of size 20
O using a sample of size 25
O constructing a 90% confidence interval
O constructing a 99% confidence interval