Exercise

Sample size for one-sided tests

Our previous sample size calculations were based on two-sided tests. Here we will show the impact of using a one-sided test on the sample size.

Instructions

100 XP

Use the power.prop.test() to calculate the sample size needed when comparing two groups with expected percentages of 10 and 30% using 80% power and a two-sided test.
Repeat using a one-sided test and display the reduction in sample size