NAME

       Statistics::Basic::Variance - find the variance of a list

SYNOPSIS

       Invoke it this way:

           my $variance = variance(1,2,3);

       Or this way:

           my $v1  = vector(1,2,3);
           my $var = var($v1);

       And then either query the values or print them like so:

           print "The variance of $v1: $variance\n";
           my $vq = $var->query;
           my $v0 = 0+$var;

       Create a 20 point "moving" variance like so:

           use Statistics::Basic qw(:all nofill);

           my $sth = $dbh->prepare("select col1 from data where something");
           my $len = 20;
           my $var = var()->set_size($len);

           $sth->execute or die $dbh->errstr;
           $sth->bind_columns( my $val ) or die $dbh->errstr;

           while( $sth->fetch ) {
               $var->insert( $val );
               if( defined( my $v = $var->query ) ) {
                   print "Variance: $v\n";
               }

               # This would also work:
               # print "Variance: $v\n" if $var->query_filled;
           }

METHODS

       new()
           The constructor takes a list of values, a single array ref, or a single
           Statistics::Basic::Vector as arguments.  It returns a Statistics::Basic::Variance
           object.

           Note: normally you'd use the mean() constructor, rather than building these by hand
           using "new()".

       query_mean()
           Returns the Statistics::Basic::Mean object used in the variance computation.

       _OVB::import()
           This module also inherits all the overloads and methods from
           Statistics::Basic::_OneVectorBase.

AUTHOR

       Paul Miller "<jettero@cpan.org>"

       I am using this software in my own projects...  If you find bugs, please please please let
       me know. :) Actually, let me know if you find it handy at all.  Half the fun of releasing
       this stuff is knowing that people use it.

OVERLOADS

       This object is overloaded.  It tries to return an appropriate string for the calculation
       or the value of the computation in numeric context.

       In boolean context, this object is always true (even when empty).

COPYRIGHT

       Copyright 2012 Paul Miller -- Licensed under the LGPL

SEE ALSO

       perl(1), Statistics::Basic, Statistics::Basic::_OneVectorBase, Statistics::Basic::Vector