Q1) Population is estimated to have standard deviation of 10. We wish to evaluate the population mean within 2, with 95 percent level of confidence. How large sample is needed?
Q2) A survey is being considered to find out the mean amount of time corporation executives watch television. Pilot survey pointed out that mean time per week is 12 hours, with a standard deviation of 3 hours. It is wished to evaluate the mean viewing time within one-quarter hour. 95 percent level of confidence is to be used. How many executives must be surveyed?
Q3) Past surveys disclose that 30% of tourists going to Las Vegas to gamble during weekend spend more than $ 1,000. Las Vegas Area Chamber of Commerce wants to update this percentage.
a) New study is to use 90% confidence level. Estimate is to be within 1 percent of population proportion. Determine the essential sample size?
b) Management said that sample size determined above is too large. What can be done to decrease the sample? Based on your suggestion recompute the sample size.