document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1120862>Question 1120862</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Out of 400 people sampled, 224 had kids. Based on this, construct a 90% confidence interval for the true population proportion of people with kids.\r<BR>\n" );
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document.write( "Give your answers as decimals, to three places\r<BR>\n" );
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document.write( "  _____   < p <   _____ <BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #736545 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=736545\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the proportion of the mean is 224/400 = 0.56<BR>\n" );
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document.write( "standard error of the sample is square root(0.56 * (1-0.56) / 400) = 0.024<BR>\n" );
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document.write( "alpha(a) = 1 - 90/100 = 0.10<BR>\n" );
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document.write( "critical probability(p*) = 1 - a/2 = 0.95<BR>\n" );
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document.write( "assuming a normal distribution, look for the z-score associated with 0.95 cumulative probability<BR>\n" );
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document.write( "z-score = 1.645<BR>\n" );
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document.write( "margin of error(ME) = 1.645 * 0.024 = 0.0395<BR>\n" );
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document.write( "the confidence interval is 0.56 + or - 0.0395<BR>\n" );
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document.write( "0.5205 < p < 0.5995<BR>\n" );
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