Question

The proportion of public accountants who have changed companies within the last three years is to be estimated within 4%. The 95% level of confidence is to be used. A study conducted several years ago revealed that the percent of public accountants changing companies within three years was 24. Round up your answers to the next whole number.

a.	To update this study, the files of how many public accountants should be studied?

b.	How many public accountants should be contacted if no previous estimates of the population proportion are available?

Answer 1

a) From standard normal tables, we get:

P( -1.96 < Z < 1.96 ) = 0.95

The margin of error given here is MOE = 0.04

It is computed as:

The sample proportion here is p = 0.24

Therefore 438 is the minimum sample size required here.

b) For no prior proportion estimate, we use p = 0.5 to get a conservative value of n. So we get here:

Therefore 601 is the minimum sample size required here.