bias in random.normalvariate??

Robert Kern robert.kern at gmail.com
Sat Aug 4 01:29:17 EDT 2007


drewlist at gmail.com wrote:
> I'm a Python newbie and certainly no expert on statistics, but my wife
> was taking a statistics course this summer and to illustrate that
> sampling random numbers from a distribution and taking an average of
> the samples gives you a random number as the result (bigger sample ->
> smaller variance in the calculated random number, converging in on the
> mean of the original distribution), I threw together this program:
> 
> #! /usr/bin/python
> 
> import random;
> 
> i=1
> samplen=100
> mean=130
> lo=mean
> hi=mean
> sd=10
> sum=0
> while(i<=samplen):
> 	x=random.normalvariate(mean,sd)
> 	#print x
> 	if x<lo: lo=x
> 	if x>hi: high=x
> 	sum+=x
> 	i+=1
> print 'sample mean=', sum/samplen, '\n'
> print 'low value =', lo
> print 'high value=', high

Your code has an error. In the middle of your code, you changed "hi" to "high".

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco




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