Question 369936: A psychologist is studying law enforcement. She wants to know about their personality traits.
a) If no preliminary study is done, how many police will need to be surveyed to be 90% sure that a point estimate of p(hat) will be within a distance of 5% from p?
****just need a doublecheck on my answer please....I have 271 police would need to be surveyed as the answer****
b) If in a random sample of police officers, it was found that 34 out of 48 were introverts, how many police will need to be surveyed to be 90% sure that a point estimate of p(hat) will be within a distance of 5% from p?
****just need a double check on my answer please....I have between 61 & 82 police would need to be surveyed as the answer.**************
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A psychologist is studying law enforcement. She wants to know about their personality traits.
a) If no preliminary study is done, how many police will need to be surveyed to be 90% sure that a point estimate of p(hat) will be within a distance of 5% from p?
****just need a doublecheck on my answer please....I have 271 police would need to be surveyed as the answer****
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Comment: 271 is correct
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b) If in a random sample of police officers, it was found that 34 out of 48 were introverts, how many police will need to be surveyed to be 90% sure that a point estimate of p(hat) will be within a distance of 5% from p?
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Solve ME = 0.05
1.645*sqrt[(1/2)(1/2)/n] = 0.05
(1/2)/sqrt(n) = 0.05/1.645
(1/2)/sqrt(n) = 0.0304
sqrt(n) = 16.45
n = 271
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Comment: Above is what I think.
Cheers,
Stan H.
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****just need a double check on my answer please....I have between 61 & 82 police would need to be surveyed as the answer.**************
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