document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1995>Question 1995</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Thank you for being there!  I'm numerically-challenged and plagued by instincts I can't make work for me.  I am trying to calculate an overall aggregate recidivism rate for three distinct groups of kids.  Each group has a distinct recidivism rate, but I need to meld them into an overall average weighted rate.  Here are my numbers for your pleasure (pleasure?):\r<BR>\n" );
document.write( "\n" );
document.write( "17 kids with a 12 percent recidivism rate<BR>\n" );
document.write( "19 kids with a 37 percent recidivism rate<BR>\n" );
document.write( "22 kids with a 55 percent recidivism rate\r<BR>\n" );
document.write( "\n" );
document.write( "Question?  What is the average recidivism rate for all these 58 kids?\r<BR>\n" );
document.write( "\n" );
document.write( "I'll treat you to lunch if you can back to me quickly; I'm preparing a summary report for our judges and there ain't a mathematician in the courthouse!  WP, administrator of Re-Entry Court.<BR>\n" );
document.write( "wally9542@cox.net </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #804 by </B><A HREF=/tutors/aboutme.mpl?userid=longjonsilver><B>longjonsilver(2297)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=longjonsilver><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=longjonsilver><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=804\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> forgive my lack of legal jargon :-)\r<BR>\n" );
document.write( "\n" );
document.write( "Group1: number of recids/17 = 0.12 --> no recids = 2  in this group<BR>\n" );
document.write( "Group2: number of recids/19 = 0.37 --> no recids = 7  in this group<BR>\n" );
document.write( "Group3: number of recids/22 = 0.55 --> no recids = 12 in this group\r<BR>\n" );
document.write( "\n" );
document.write( "so combined, total number of recids = 21<BR>\n" );
document.write( "and total number of offenders = 58\r<BR>\n" );
document.write( "\n" );
document.write( "so mean value = (21/58)*100 = 36%\r<BR>\n" );
document.write( "\n" );
document.write( "NEVER EVER EVER EVER just add the 3 means and divide by 3...the 3 sets have different sizes and so their is a weighting.\r<BR>\n" );
document.write( "\n" );
document.write( "Jon. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );