# [Numpy-discussion] non-standard standard deviation

yogesh karpate yogeshkarpate@gmail....
Fri Dec 4 06:18:45 CST 2009

```@ Pauli and @ Colin:
Sorry for the late reply. I was busy in
some other assignments.
# As far as  normalization by(n) is concerned then its common assumption
that the population is normally distributed and population size is fairly
large enough to fit the normal distribution. But this standard deviation,
when applied to a small population, tends to be too low therefore it is
called  as biased.
# The correction known as bessel correction is there for small sample size
std. deviation. i.e. normalization by (n-1).
# In "electrical-and-electronic-measurements-and-instrumentation" by A.K.
Sawhney . In 1st chapter of the book "Fundamentals of Meausrements " . Its
shown that for N=16 the std. deviation normalization was (n-1)=15
# While I was learning statistics in my course Instructor would advise to
take n=20 for normalization by (n-1)
# Probability and statistics by Schuam Series  is good reading.
Regards
~ymk
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