function SetUpServer() {
TopHeader = "<HTML><title>Statistics with GAWK</title>"
TopDoc = "<BODY>\
<h2>Please choose one of the following actions:</h2>\
<UL>\
<LI><A HREF=" MyPrefix "/AboutServer>About this server</A></LI>\
<LI><A HREF=" MyPrefix "/EnterParameters>Enter Parameters</A></LI>\
</UL>"
TopFooter = "</BODY></HTML>"
GnuPlot = "gnuplot 2>&1"
m1=m2=0; v1=v2=1; n1=n2=10
}
function HandleGET() {
if(MENU[2] == "AboutServer") {
Document = "This is a GUI for a statistical computation.\
It compares means and variances of two distributions.\
It is implemented as one GAWK script and uses GNUPLOT."
} else if (MENU[2] == "EnterParameters") {
Document = ""
if ("m1" in GETARG) { # are there parameters to compare?
Document = Document "<SCRIPT LANGUAGE=\"JavaScript\">\
setTimeout(\"window.open(\\\"" MyPrefix "/Image" systime()\
"\\\",\\\"dist\\\", \\\"status=no\\\");\", 1000); </SCRIPT>"
m1 = GETARG["m1"]; v1 = GETARG["v1"]; n1 = GETARG["n1"]
m2 = GETARG["m2"]; v2 = GETARG["v2"]; n2 = GETARG["n2"]
t = (m1-m2)/sqrt(v1/n1+v2/n2)
df = (v1/n1+v2/n2)*(v1/n1+v2/n2)/((v1/n1)*(v1/n1)/(n1-1) \
+ (v2/n2)*(v2/n2) /(n2-1))
if (v1>v2) {
f = v1/v2
df1 = n1 - 1
df2 = n2 - 1
} else {
f = v2/v1
df1 = n2 - 1
df2 = n1 - 1
}
print "pt=ibeta(" df/2 ",0.5," df/(df+t*t) ")" |& GnuPlot
print "pF=2.0*ibeta(" df2/2 "," df1/2 "," \
df2/(df2+df1*f) ")" |& GnuPlot
print "print pt, pF" |& GnuPlot
RS="\n"; GnuPlot |& getline; RS="\r\n" # $1 is pt, $2 is pF
print "invsqrt2pi=1.0/sqrt(2.0*pi)" |& GnuPlot
print "nd(x)=invsqrt2pi/sd*exp(-0.5*((x-mu)/sd)**2)" |& GnuPlot
print "set term png small color" |& GnuPlot
#print "set term postscript color" |& GnuPlot
#print "set term gif medium size 320,240" |& GnuPlot
print "set yrange[-0.3:]" |& GnuPlot
print "set label 'p(m1=m2) =" $1 "' at 0,-0.1 left" |& GnuPlot
print "set label 'p(v1=v2) =" $2 "' at 0,-0.2 left" |& GnuPlot
print "plot mu=" m1 ",sd=" sqrt(v1) ", nd(x) title 'sample 1',\
mu=" m2 ",sd=" sqrt(v2) ", nd(x) title 'sample 2'" |& GnuPlot
print "quit" |& GnuPlot
GnuPlot |& getline Image
while ((GnuPlot |& getline) > 0)
Image = Image RS $0
close(GnuPlot)
}
Document = Document "\
<h3>Do these samples have the same Gaussian distribution?</h3>\
<FORM METHOD=GET> <TABLE BORDER CELLPADDING=5>\
<TR>\
<TD>1. Mean </TD>
<TD><input type=text name=m1 value=" m1 " size=8></TD>\
<TD>1. Variance</TD>
<TD><input type=text name=v1 value=" v1 " size=8></TD>\
<TD>1. Count </TD>
<TD><input type=text name=n1 value=" n1 " size=8></TD>\
</TR><TR>\
<TD>2. Mean </TD>
<TD><input type=text name=m2 value=" m2 " size=8></TD>\
<TD>2. Variance</TD>
<TD><input type=text name=v2 value=" v2 " size=8></TD>\
<TD>2. Count </TD>
<TD><input type=text name=n2 value=" n2 " size=8></TD>\
</TR> <input type=submit value=\"Compute\">\
</TABLE></FORM><BR>"
} else if (MENU[2] ~ "Image") {
Reason = "OK" ORS "Content-type: image/png"
#Reason = "OK" ORS "Content-type: application/x-postscript"
#Reason = "OK" ORS "Content-type: image/gif"
Header = Footer = ""
Document = Image
}
}