# Thread: [RESOLVED] Random number with statistical distribution

1. ## [RESOLVED] Random number with statistical distribution

I need help converting a Math.random() number into something that would simulate the distribution curve. For example, if the mean were 10.0 and a standard distribution was 1.0, the returned random number would be more likely to be between 10.0-10.5 than 10.5-11.0 and something > 13 would be extremely rare.

2. Got it. I ran the random function 20 times, summing the results. After tweaking the factor by running it 100,000 times, I got:
Code:
```<html><head><title>Rubato test</title>
<script language="JavaScript">
function startup() {document.tournform.Compute.focus();}
function playOne() {
var randSum=0;
for (var i=0; i < 20; i++)
randSum+= Math.random();
return (randSum * 0.777) - 7.77;
return r;
}

function calculate() {
var OutText = "";
var sum=0;
var sumSq=0;
var Min = 100000
var Max =-100000
var StdD = 0

for (var i = 0; i < 100000; i++) {
var x = playOne();
sum += x;
sumSq += x * x;
if (Min > x) Min = x;
if (Max < x) Max = x;
}
mean = sum / 100000
StdD = Math.sqrt( sumSq / 100000 - mean * mean);
OutText = "The mean is " + mean + " min value = " + Min + " max value = " + Max + "\n Std deviation = " + StdD;
document.tournform.OutputField.value = OutText;
}

</script>

<form name="tournform" onSubmit="calculate();return false;">
<table width="550" height="228">
<tr>
<td colspan="3" width="500" height="24">
<b><big>Test Rubato:</big></b>
</td>
</tr>
<tr>

<td width="347"><input type=button name="Compute" value="Compute" onClick="calculate()"></td>
</tr>
<tr>
<td colspan=3 width="500" height="167">
<textarea name="OutputField" rows="21" cols="80"></textarea></td></tr>
</table>
</form>

</form>
<p><font size="4">This script tests a random number generator 10000 times and displays the results.</font><br>
</body>
</html>```

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