Question 1133246
Margin of Error(ME) = 0.04
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critical statistic(z) for a 90% confidence level is 1.645
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when standard deviation is not known, we use
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sample size n = p*(1-p)*(z/ME)^2, where p is the proportion
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a) n = 0.58 * (1-0.58)*(1.645/0.04)^2 = 411.9923
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sample size is 412
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b) p is not known, so use p = 0.50
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n = 0.50 * (1-0.50)*(1.645/0.04)^2 = 422.8164
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sample size is 423 
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