document.write( "Question 877478: Unsolved 2014-05-23 14:28:27 Determine a 90% confidence interval for μ if σ=5, x̄ (x bar) = 70 and n=82. Give answer interval rounded to two decimal places. Thank you!
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Algebra.Com's Answer #529383 by jim_thompson5910(35256) $\"\"$ $\"About$

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The critical value for a 90% confidence interval is z = 1.645 (you use a calculator or table to find this)\r
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\n" ); document.write( "\n" ); document.write( "Given\r
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\n" ); document.write( "\n" ); document.write( "xbar = 70
\n" ); document.write( "z = 1.645 (see above)
\n" ); document.write( "sigma = 5
\n" ); document.write( "n = 82\r
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\n" ); document.write( "\n" ); document.write( "Lower Bound \r
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\n" ); document.write( "\n" ); document.write( "L = xbar - z*sigma/sqrt(n)
\n" ); document.write( "L = 70 - 1.645*5/sqrt(82)
\n" ); document.write( "L = 69.0917006980343
\n" ); document.write( "L = 69.09\r
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\n" ); document.write( "\n" ); document.write( "Upper Bound \r
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\n" ); document.write( "\n" ); document.write( "U = xbar + z*sigma/sqrt(n)
\n" ); document.write( "U = 70 + 1.645*5/sqrt(82)
\n" ); document.write( "U = 70.9082993019657
\n" ); document.write( "U = 70.91\r
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\n" ); document.write( "\n" ); document.write( "The confidence interval (L,U) is (69.09, 70.91)\r
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