Although airline schedules and cost are important factors for business travelers when choosing an airline carrier , a USA Today survey found that business travelers list an airline's frequent flyer program as the most important factor . From a sample of 1993 business travelers who responded to the survey , 618 listed a frequent flyer program as the most important factor .

a . What is the point estimate of the proportion of the population of business travelers who believe a frequent flyer program is the most important factor when choosing an airline carrier?

b . Develop a 95 % confidence interval estimate of the population proportion .

c . How large a sample would be required to report the margin of error of .01 at 95 % confidence ? Would you recommend that USA Today attempt to provide this degree of precision ? Why or why not ?