Q1. Suppose that the average weekly earnings for employees in general automotive repair shops is $470, and that the standard deviation for the weekly earnings for such employees is $60. A sample of 100 such employees is selected at random. The mean and standard deviation of the sampling distribution of the average weekly earnings in the sample are 470 and 6, respectively. Find the probability that the mean of the sample is greater than $480.
Q2. You have been assigned to determine whether more people prefer Coke to Pepsi. Assume that roughly half the population prefers Coke and half prefers Pepsi. How large a sample would you need to take to ensure that you could estimate, with 90% confidence, the proportion of people preferring Coke within 5% of the actual value?