document.write( "Question 1197051: a. A statistics practitioner calculated the mean and standard deviation from a sample of 51. They are x bar = 120 and s = 15. Estimate the population mean with 95% confidence.\r
\n" ); document.write( "\n" ); document.write( "b. Repeat part (a) with a 90% confidence level.\r
\n" ); document.write( "\n" ); document.write( "c. Repeat part (a) with an 80% confidence level.\r
\n" ); document.write( "\n" ); document.write( "d. What is the effect on the confidence interval estimate of decreasing the confidence level? \n" ); document.write( "

Algebra.Com's Answer #830150 by ewatrrr(24785) $\"\"$ $\"About$

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document.write( "Hi\r\n" );
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document.write( "Using Excel Function:\r\n" );
document.write( "=CONFIDENCE(alpha, sd, size)\r\n" );
document.write( "       (to one decimal point) ME \r\n" );
document.write( "=CONFIDENCE.T(.05, 15, 51) = 4.2  95%   CI = 120 - 4.2 <  < 120 + 4.2\r\n" );
document.write( "=CONFIDENCE.T(.1, 15, 51) =  3.5  90%   CI = 120 - 3.5 <  < 120 + 3.5\r\n" );
document.write( "=CONFIDENCE.T(.2, 15, 51) =  2.7  80%   CI = 120 - 2.7 <  < 120 + 2.7\r\n" );
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document.write( "Effect on the confidence interval estimate of decreasing the confidence level:\r\n" );
document.write( " ME gets smaller ⇒  Interval gets smaller\r\n" );
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document.write( "Using ME =\r\n" );
document.write( "One can see as z gets smaller ⇒  ME gets smaller ⇒ Interval gets smaller\r\n" );
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document.write( "Wish You the Best in your Studies. \r\n" );
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