SOLUTION: A survey was conducted to determine the percentage of students at a post secondary institution who prefer the new alpha-grading system. The responses from a random sample of 30 stu

Question 749084: A survey was conducted to determine the percentage of students at a post secondary institution who prefer the new alpha-grading system. The responses from a random sample of 30 students are shown below.
YES-18, NO-12
Construct a 98.5% confidence interval for a population proportion who prefer the new alpha-grading system.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A survey was conducted to determine the percentage of students at a post secondary institution who prefer the new alpha-grading system. The responses from a random sample of 30 students are shown below.
YES-18, NO-12
Construct a 98.5% confidence interval for a population proportion who prefer the new alpha-grading system.
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Note: 0.985-1 = 0.015
(1/2)0.015 = 0.0075
invNorm(0.0075) = 2.4324
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p-hat = 18/30 = 0.6
ME = 2.4324*sqrt[0.6*0.4/30] = 0.2176
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98.5% CI: 0.6-0.2176 < P < 0.6+0.2176
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Cheers,
Stan H.
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