Activity. Find the sample size of each of the following: 1. 90% confidence, 0 = 25, E - 3 2. 98% confidence, E - 2.6, p=0.37 3 Yellow Bus Lines, Inc. wants to know the amount of time it takes its bus to travel from one bus stop to the next. From the past observations, the standard deviation is 25 minutes. How many samples are needed in order to be 98% sure that that the maximum error of estimate is 5 minutes? 4. You want to know the average number of hours a student spends each day in watching Korean Drama Series. The standard deviation from previous study is 3.7 hours. How large a sample must be selected if you wants to be 95% confident of finding whether the true mean differs from the sample mean by half an hour