he Island Cab Company has 20 cabs. The local manager wants to conduct a work sampling study to determine what proportion of the time a cab driver is sitting idle, which he estimates is about 40%. The plan is to observe at random the cabs during a five-day period by the dispatcher, who simply called each cab and checked on its status. The manager wants the estimate to be within 5% of the proportion, with an 92% level of confidence. (2 decimals are adequate)

a. Determine the sample size for this work sampling study.

b. After 10 observations, (Each observation is for all 20 cabs) it was noted that a total of 75 cabs were idle. With this new data determine the revised sample size for the study.