SOLUTION: The proportion of public accountants who have changed companies within the last three years is to be estimated within 4%. The 90% level of confidence is to be used. A study conduct

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Question 959998: The proportion of public accountants who have changed companies within the last three years is to be estimated within 4%. The 90% 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 23.

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 by stanbon(75887) About Me  (Show Source):
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The proportion of public accountants who have changed companies within the last three years is to be estimated within 4%. The 90% 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 23.

a.To update this study, the files of how many public accountants should be studied?
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n = [z/E]^2*pq
n = [1.2816/0.04]^2 *0.23*0.77 = 182 when rounded up
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b.How many public accountants should be contacted if no previous estimates of the population proportion are available?
n = [z/E]^2*(1/2)(1/2) = [1.2816/0.04]^2*(1/4) = 257 when rounded up
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Cheers,
Stan H.
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