NAME

Statistics::Basic A collection of very basic statistics formulae for vectors.

SYNOPSIS

# for use with one vector:
Statistics::Basic::Mean;
Statistics::Basic::Variance;
Statistics::Basic::StdDev;

# for use with two vectors:
Statistics::Basic::CoVariance;
Statistics::Basic::Correlation;

EXAMPLES

my $mean = Statistics::Basic::Mean->new($array_ref)->query;

print "$mean\n";  # hooray

# That works, but I needed to calculate a LOT of means for a lot of
# arrays of the same size.  Furthermore, I needed them to operate FIFO
# style.  So, they do:

my $mo = new Statistics::Basic::Mean([1..3]);

print $mo->query, "\n"; # the avearge of 1, 2, 3 is 2
      $mo->insert(4);   # Keeps the vector the same size automatically
print $mo->query, "\n"; # so, the average of 2, 3, 4 is 3

# You might need to keep a running average, so I included a growing
# insert

      $mo->ginsert(5);  # Expands the vector size by one and appends a 5
print $mo->query, "\n"; # so, the average is of 2, 3, 4, 5 is 7/2

# And last, you might need the mean of [3, 7] after all the above

      $mo->set_vector([2,3]);  # *poof*, the vector is 2, 3!
print $mo->query, "\n"; # and the average is now 5/2!  Tadda!

# These functions all work pretty much the same for ::StdDev and
# ::Variance but they work slightly differently for CoVariance and
# Correlation.

# Not suprisingly, the correlation of [1..3] and [1..3] is 1.0

my $co = new Statistics::Basic::Correlation( [1..3], [1..3] );

print $co->query, "\n";

# Cut the correlation of [1..3, 7] and [1..3, 5] is less than 1

      $co->ginsert( 7, 5 );
print $co->query, "\n";

BUGS

Besides the lack of documentation?  Well, I'm sure there's a bunch.
I've tried to come up with a comprehensive suite of tests, but it's
difficult to think of everything.

If you spot any bugs, please tell me.

ENV VARIABLES

DEBUG

Try setting $ENV{DEBUG}=1; or $ENV{DEBUG}=2; to see the internals.

Also, from your bash prompt you can 'DEBUG=1 perl ./myprog.pl' to
enable debugging dynamically.

UNBIAS

This module uses the sum(X - mean(X))/N definition of variance.
If you wish to use the unbiased, sum(X-mean(X)/(N-1) definition, then 
set the $ENV{UNBIAS}=1;

# And if you thought that was useful, then give a shout out to:
# Robert McGehee <xxxxxxxx@wso.williams.edu>, for he requested it.

AUTHOR

Please contact me with ANY suggestions, no matter how pedantic.

Jettero Heller <japh@voltar-confed.org>

COPYRIGHT

GPL!!  I included a gpl.txt for your reading enjoyment.

SEE ALSO

Most of the documentation is very thin.  Sorry.  The modules with their
own documentation (no matter how thin) are listed below.

Statistics::Basic::LeastSquareFit