Paul Miller > Statistics-Basic-1.6607 > Statistics::Basic::Variance

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# 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.