1. The Bide-a-While efficiency hotel, which caters to business workers who stay for extended periods of time (weeks or months), offers room service. The marketing director is interested in trying to find out whether or not she can advertise "room service in under thirty minutes, or order is free". You will be asked to determine how many delivery times she should sample to estimate the true mean delivery time to within 5 minutes at the 90% reliability level? Suppose that the standard deviation for delivery times is 18.2 minutes.
2. According to a recent poll, 16.2% of credit cardholders in United States shave employed their credit card to make a purchase on internet. You will be asked to recognize how large a sample must be taken if the true proportion is to be estimated to in 1.5% at the 95% reliability level? You might use the sample proportion in calculation of sample size.