Statistics::Basic::VarUsereContributed Perl DocuStatistics::Basic::Variance(3)NAMEStatistics::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;
}
METHODSnew()
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 2009 Paul Miller -- Licensed under the LGPL
SEE ALSOperl(1), Statistics::Basic, Statistics::Basic::_OneVectorBase,
Statistics::Basic::Vector
perl v5.14.1 2009-06-28 Statistics::Basic::Variance(3)
