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Postings from March 2002
This might seem trivial, but it has me stumped.
The variance of numbers 0..20 is 38.5.
Then why does Math:NumberCruncher show it as 36.6667?
Here's a sample prog, and it's output. Here test04.dat is a file that has
numbers 0 to 20, on separate lines.
#-------------------start----------------
#!/usr/bin/perl -w
use Math::NumberCruncher;
# Program to test Math::NumberCruncher
# Get a file from STDIN, print the variance, and the std. deviation.
@array = <>;
map {chomp} @array;
$variance = Math::NumberCruncher::Variance(\@array);
$stddev = Math::NumberCruncher::StandardDeviation(\@array);
$sd2 = $stddev**2;
print scalar(@array), "\n";
printf "Var=$variance, S.D=$stddev S.D^2 = $sd2\n";
exit;
#----------------end---------------------
And the output is:
21
Var=36.6666666666667, S.D=6.05530070819498 S.D^2 = 36.6666666666667
What could be possibly wrong? Even the standard value is wrong.
TIA,
-tir
--
Tirthankar, IGIDR.
+91-22-8400919 x275 (r), x593(o), x542(CFL).
http://www.igidr.ac.in/~tir
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tears.
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