document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1185010>Question 1185010</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The Prior to medical visits, patients are asked to complete a self-administered medical history<BR>\n" );
document.write( "form. The time it takes each patient to complete the form is approximately normally distributed,<BR>\n" );
document.write( "with a mean of 12.4 minutes and a standard deviation of 2.1 minutes.<BR>\n" );
document.write( "a) What proportion of patients completes the medical history form in 10 minutes or less?<BR>\n" );
document.write( "b) What proportion of patients takes 20 minutes or more to complete the medical history form?<BR>\n" );
document.write( "c) What is the 90th percentile of the time to complete the medical history form? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #815728 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=815728\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> z=(x-mean)/sd<BR>\n" );
document.write( "a.z < (10-12.4)/2.1<BR>\n" );
document.write( " =-1.14<BR>\n" );
document.write( "that probability is 0.1271<BR>\n" );
document.write( "-<BR>\n" );
document.write( "b. z > (20-12.4)/2.1<BR>\n" );
document.write( "=7.6/2.1<BR>\n" );
document.write( "=3.62<BR>\n" );
document.write( "that probability is 0.00015<BR>\n" );
document.write( "-<BR>\n" );
document.write( "90th percentile is z=+1.282<BR>\n" );
document.write( "1.282=(x-12.4)/2.1<BR>\n" );
document.write( "2.69=x-12.4<BR>\n" );
document.write( "x=15.1 minutes<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );