document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1161797>Question 1161797</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The lengths of a particular​ animal's pregnancies are approximately normally​ distributed, with mean muequals250 days and standard deviation sigmaequals12 days.<BR>\n" );
document.write( "​(a) What proportion of pregnancies lasts more than 256 ​days?<BR>\n" );
document.write( "​(b) What proportion of pregnancies lasts between 232 and 259 ​days?<BR>\n" );
document.write( "​(c) What is the probability that a randomly selected pregnancy lasts no more than 244 ​days?<BR>\n" );
document.write( "​(d) A​ \"very preterm\" baby is one whose gestation period is less than 223 days. Are very preterm babies​ unusual? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #785421 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=785421\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> z=(x-mean)/sd<BR>\n" );
document.write( "a.  z is more than 6/12 or 1/2.That probability is 0.3085<BR>\n" );
document.write( "b.  z is between -1.5 and +0.75 with probability of 0.7066<BR>\n" );
document.write( "c. z is less than -0.5, and since the curve is symmetrical, that is the same answer as a or 0.3085 probability <BR>\n" );
document.write( "d. z is less than -2.25 or 0.0122. Uncommon but given the number of babies born is uncommon for sure.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );