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Math Related
Random Distribution
Generate normally distributed random numbers by entering a mean value and standard deviation. Uses the normal law of error to determine an events given probability. Neat!
The JavaScript Source: Math Related: Random Distribution
Simply click inside the window below, use your cursor to highlight the script, and copy (type Control-c or Apple-c) the script into a new file in your text editor (such as Note Pad or Simple Text) and save (Control-s or Command-s). The script is yours!!!
<!-- TWO STEPS TO INSTALL RANDOM DISTRIBUTION:
1. Copy the coding into the HEAD of your HTML document
2. Add the last code into the BODY of your HTML document -->
<!-- STEP ONE: Paste this code into the HEAD of your HTML document -->
<HEAD>
<SCRIPT LANGUAGE="JavaScript">
<!-- Original: Phil Pavlik (ppavlik@nmu.edu) -->
<!-- Contributor URL: http://chemistry.nmu.edu/ppavlik -->
<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->
<!-- Begin
function calculate() {
var mean, sdev, N, sign, sum, str;
var y = Array(), x = Array(), freq = Array();
mean = document.statForm.m.value * 1;
sdev = document.statForm.s.value * 1;
N = document.statForm.n.value * 1;
sdevsq = sdev * sdev;
for(var i = 0; i <= N; i++) {
yr = 1;
yxr = 0;
while(yr > yxr) {
xr = 500 * sdev * Math.random();
yr = 100 * Math.random();
yxr = 100 * Math.exp(-(xr) * (xr) / (2 * sdevsq));
}
s = 1;
if(Math.random() < .5)
s = -1;
x[i] = mean + s * xr;
}
str = "";
for(var i = 1; i <= N; i++) {
str = str + x[i] + "\n";
}
sum = 0;
for(var i = 1; i <= N; i++) {
sum = sum + x[i];
}
mean = sum / N;
sum = 0;
for(var i = 1; i <= N; i++) {
sum = sum + (x[i] - mean) * (x[i] - mean)
}
sdev = Math.sqrt((sum) / (N - 1));
document.statForm.vals.value = str;
document.statForm.mm.value = mean;
document.statForm.ss.value = sdev;
}
// End -->
</script>
</HEAD>
<!-- STEP TWO: Copy this code into the BODY of your HTML document -->
<BODY>
<center>
<form name=statForm>
<table cellpadding=0 bgcolor=black>
<tr>
<td>
<table border=0 cellpadding=5 bgcolor=ffffcc>
<tr>
<td colspan=2>
<center>
<font face=arial size=2>
<b>GENERATION OF A RANDOM SET OF NORMALLY DISTRIBUTED VALUES</b>
</font>
</center>
</td>
</tr>
<tr>
<td colspan=2>
<center>
<b>Normal Law Universe Parameters
</center>
</td>
</tr>
<tr>
<td>
<b>Mean value = <input type=text name="m" size=15></b>
</td>
<td>
<b>Std. Deviation = <input type=text name="s" size=15></b>
</td>
</tr>
<tr>
<td colspan=2>
<center>
<b>Number of points to generate = <input type=text name="n" size=10></b>
<input type=button value="Generate Sample" onClick="calculate()">
</center>
</td>
</tr>
<tr>
<td>
<center>
<b>Calculated Random Sample values</b>
<br>
<textarea name=vals rows=5 cols=20></textarea>
</center>
</td>
<td valign=top>
<center>
<b>Calculated Sample Properties</b>
<br>
<br>
<b>Mean value = <input type=text name="mm" size=20>
<br>
Std. Deviation = <input type=text name="ss" size=20>
</b>
</center>
<br>
</td>
</tr>
</table>
</td>
</tr>
</table>
</form>
</center>
<p><center>
<font face="arial, helvetica" size"-2">Free JavaScripts provided<br>
by <a href="http://javascriptsource.com">The JavaScript Source</a></font>
</center><p>
<!-- Script Size: 3.13 KB --> Did you use this script? Do you like this site? Please link to us!