in reply to Excel or Perl for simple statistics?
There are generally two types of standard deviation calculations, one for when your data represents a sample of the population, and one where it represents the whole population. The former divides the squared deviations by N-1 (the sample count minus 1), whereas the latter divides by N.
As pryrt points out, you can get Statistics::Basic to do both by setting UNBIAS to true, whereas Statistics::Lite gives you two separate functions. Note also that Statistics::Basic defaults to a precision of 2 decimal points - this can be changed by setting IPRES to the desired precision.
Just for fun I did a little comparison table:
Excel | STDEV | 0.41068873 | STDEVP | 0.400791162 |
Open Office | STDEV | 0.4106887305 | STDEVP | 0.400791162 |
Statistics::Lite | stddev() | 0.410688730467897 | stddevp() | 0.400791162022762 |
Statistics::Basic | stddev() UNBIAS true |
0.410688730467897 | stddev() | 0.400791162022762 |
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