Your 20 observations of Dr. Knowitall reveal the following information. Assume that the estimate is to be within 5 percent of the true proportion 95 percent of the time.

Activity Observed ...... Number of Times Observed

With patient .............. 6

Reviewing test results ........... 3

On phone ................ 2

Idle ................... 1

Away on emergency ........... 4

Not available ............... 4

(a) Calculate the sample size needed to estimate the proportion of time Dr. Knowitall spends away on emergencies.

(b) Calculate the sample size needed to estimate the proportion of time Dr. Knowitall spends reviewing test results.

(c) Calculate the minimum number of observations that must be made to complete the work-sampling analysis.