document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1162704>Question 1162704</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The standard deviation of a normal population is 10.you take a sample of 25 item from this population and compute a 95% confidence interval. In order to compute the confidence interval, you will use? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #786594 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=786594\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> sd = 10<BR>\n" );
document.write( "n = 25<BR>\n" );
document.write( "se = sd / sqrt(n) = 10 / sqrt(25) = 10 / 5 = 2<BR>\n" );
document.write( "95% confidence interval requires two ended alpha to be equal to .05.<BR>\n" );
document.write( ".05/2 means alpha os .025 on each end.<BR>\n" );
document.write( "z-score required will be plus or minus the z-score that has .025 area to the left of it.<BR>\n" );
document.write( "that critical z-score will be plus or minus 1.959963986<BR>\n" );
document.write( "to find the associated raw score, you would need the mean.<BR>\n" );
document.write( "unfortunately, the mean is missing from the problem statement.<BR>\n" );
document.write( "i think the answer to your question is that you would use the standard error, otherwise known at the standard deviation of the distribution of sample means.<BR>\n" );
document.write( "that's the formula i showed you above of se = sd / sqrt(n).\r<BR>\n" );
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document.write( " </SPAN>\n" );
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