Question 959412: A survey asked, "How important is it to you to buy products that are made in America?" Of the 600 Americans surveyed, 450 responded, "It is important." For each of the following levels of confidence, find the sample proportion and the margin of error associated with the poll. (Round the margin of error to one decimal place.)
(a) a 90% level of confidence
sample proportion :
margin of error ± :
(b) a 99% level of confidence
sample proportion :
margin of error :
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A survey asked, "How important is it to you to buy products that are made in America?" Of the 600 Americans surveyed, 450 responded, "It is important." For each of the following levels of confidence, find the sample proportion and the margin of error associated with the poll. (Round the margin of error to one decimal place.)
(a) a 90% level of confidence
sample proportion :45/60 = 3/4
margin of error ± : 1.645*sqrt[(3/4)(1/4)/600] = 0.029
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(b) a 99% level of confidence
sample proportion : 3/4
margin of error : 2.5758sqrt[(3/4)(1/4)/600] = 0.0177
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Cheers,
Stan H.
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