document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=964684>Question 964684</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please Help Someone!<BR>\n" );
document.write( "Find the indicated probability or percentage for the normally distributed variable.<BR>\n" );
document.write( "The lengths of human pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. What is the probability that a pregnancy lasts at least 300 days? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #589542 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=589542\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> We want the Probability (X < 300)<BR>\n" );
document.write( "First calculate the z-score <BR>\n" );
document.write( "z-score = X - mean / std dev = (300 - 268) / 15 = 2.133333333 approx 2.13<BR>\n" );
document.write( "now consult the table of z-scores for the probability associated with a z-score of 2.13<BR>\n" );
document.write( "Probability (X < 300) = 0.9834 approx 0.98<BR>\n" );
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