SOLUTION: In a survey of 1002 people, 701 said that they voted in a recent presidental election (based on data from ICR Research Group). Voting records show that 61% of eligible voters actua

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Question 126658This question is from textbook Elementary Statistics
: In a survey of 1002 people, 701 said that they voted in a recent presidental election (based on data from ICR Research Group). Voting records show that 61% of eligible voters actually did vote.
a. Find a 99% confidence interval estimate of the proportion of people who say that they voted.
b. Are the results consistent with the actual voter turnout of 61% why or why not?
This question is from textbook Elementary Statistics

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
In a survey of 1002 people, 701 said that they voted in a recent presidental election (based on data from ICR Research Group). Voting records show that 61% of eligible voters actually did vote.
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a. Find a 99% confidence interval estimate of the proportion of people who say that they voted.
p-hat = x/n = 701/1002 = 0.6996
E=z*sqrt[(p-hat)(q-hat)/n]
= 2.575*sqrt[(0.6996)(0.3004)/1002] = 0.037292
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99% C.I.: (0.6996-0.03729,0.6996+0.0729)
= (0.662308,0.736892)
b. Are the results consistent with the actual voter turnout of 61% why or why not?
No, because 61% does not fall in the confidence interval
range of values for p.
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Cheers,
Stan H.