document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1203889>Question 1203889</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The lengths of pregnancies in a small rural village are normally distributed with a mean of 270 days and a standard deviation of 15 days. A distribution of values is normal with a mean of 270 and a standard deviation of 15.\r<BR>\n" );
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document.write( "What percentage of pregnancies last fewer than 257 days?<BR>\n" );
document.write( "P(X < 257 days) = %\r<BR>\n" );
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document.write( "Enter your answer as a percent accurate to 1 decimal place (do not enter the \"%\" sign). Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #839827 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=839827\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> population mean is 270 days.<BR>\n" );
document.write( "population standard deviation is 15 days.<BR>\n" );
document.write( "test value = 257 days.\r<BR>\n" );
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document.write( "use z-score formula.<BR>\n" );
document.write( "z = (x - m) / 15 becomes z = (257 - 270) / 15 = -.86667<BR>\n" );
document.write( "z is the z-score<BR>\n" );
document.write( "x is the test value<BR>\n" );
document.write( "m is the mean<BR>\n" );
document.write( "s is the standard deviation.\r<BR>\n" );
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document.write( "area to the left of z-score of -.86667 = .1931.<BR>\n" );
document.write( "this means there is a 19.3% probability of a pregnancy lasting less than 257 days.<BR>\n" );
document.write( "you would enter 19.3 as your solution is what i think based on the instructions.\r<BR>\n" );
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