document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=742883>Question 742883</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the number of hours a week students devotes to study is normally distributed,with a mean of 30 hours and a standard deviation of 8 hours.<BR>\n" );
document.write( "a. what percent of student will study less than 20 hours?<BR>\n" );
document.write( "b.what percent of students will study more than 35 hours?<BR>\n" );
document.write( "c. out of a class of 200 students, how many will study between 25 and 35 hours? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #452661 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=452661\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the number of hours a week students devotes to study is normally distributed,with a mean of 30 hours and a standard deviation of 8 hours.<BR>\n" );
document.write( "a. what percent of student will study less than 20 hours?<BR>\n" );
document.write( "z(20) = (20-30)/8 = -10/8 = -5/4<BR>\n" );
document.write( "P(x < 20) = P(z < -5/4) = normalcdf(-100,-5/4) = 0.1056<BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "Use the same procedure on problems \"b\" and \"c\".<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "===================<BR>\n" );
document.write( "b.what percent of students will study more than 35 hours?<BR>\n" );
document.write( "c. out of a class of 200 students, how many will study between 25 and 35 hours?<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );