Q1) Bide-a-While efficiency hotel, which caters to business workers who remain for extended periods of time (weeks or months), offers room service. Marketing director is interested in trying to find out whether or not she can advertise "room service in under 30 minutes, or order is free".  You will be asked to recognize how many delivery times she must sample to evaluate true mean delivery time to within 5 minutes at 90% reliability level?   Suppose that standard deviation for delivery times is 18.2 minutes. 

Q2) According to new poll, 16.2% of credit cardholders in United States shave used their credit card to create a purchase on internet.  You will be asked to recognize how large sample must be taken if true proportion is to be evaluated to within 1.5% at 95% reliability level?  You may use sample proportion in computations of the sample size.