document.write( "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.
\n" ); document.write( "YES-18, NO-12
\n" ); document.write( "Construct a 98.5% confidence interval for a population proportion who prefer the new alpha-grading system. \n" ); document.write( "

Algebra.Com's Answer #455795 by stanbon(75887) $\"\"$ $\"About$

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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.
\n" ); document.write( "YES-18, NO-12
\n" ); document.write( "Construct a 98.5% confidence interval for a population proportion who prefer the new alpha-grading system.
\n" ); document.write( "------
\n" ); document.write( "Note: 0.985-1 = 0.015
\n" ); document.write( "(1/2)0.015 = 0.0075
\n" ); document.write( "invNorm(0.0075) = 2.4324
\n" ); document.write( "-------------------------------
\n" ); document.write( "p-hat = 18/30 = 0.6
\n" ); document.write( "ME = 2.4324*sqrt[0.6*0.4/30] = 0.2176
\n" ); document.write( "----------------------
\n" ); document.write( "98.5% CI: 0.6-0.2176 < P < 0.6+0.2176
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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