document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1073762>Question 1073762</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The lengths of pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. If 64 women are randomly selected, find the probability that they have a mean pregnancy between 266 days and 268 days. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #688547 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=688547\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The lengths of pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. If 64 women are randomly selected, find the probability that they have a mean pregnancy between 266 days and 268 days. <BR>\n" );
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document.write( "z(266) = (266-268)/[15/sqrt(64)] = -2/(15/8) = -1.0667<BR>\n" );
document.write( "z(268) = 0<BR>\n" );
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document.write( "P(266<= x <= 268) = P(-1<= z <=0) = normalcdf(-1.0667,0) = 0.3569<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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