Statistics::Basic::StdDev(3pm) | User Contributed Perl Documentation | Statistics::Basic::StdDev(3pm) |
Statistics::Basic::StdDev - find the standard deviation of a list
Invoke it this way:
my $stddev = stddev(1,2,3);
Or this way:
my $v1 = vector(1,2,3); my $std = stddev($v1);
And then either query the values or print them like so:
print "The stddev of $v1: $std\n"; my $sq = $std->query; my $s0 = 0+$std;
Create a 20 point "moving" stddev like so:
use Statistics::Basic qw(:all nofill); my $sth = $dbh->prepare("select col1 from data where something"); my $len = 20; my $std = stddev()->set_size($len); $sth->execute or die $dbh->errstr; $sth->bind_columns( my $val ) or die $dbh->errstr; while( $sth->fetch ) { $std->insert( $val ); if( defined( my $s = $std->query ) ) { print "StdDev: $s\n"; } # This would also work: # print "StdDev: $s\n" $std->query_filled; }
Note: normally you'd use the mean() constructor, rather than building these by hand using "new()".
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).
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.
Copyright 2012 Paul Miller -- Licensed under the LGPL
perl(1), Statistics::Basic, Statistics::Basic::_OneVectorBase, Statistics::Basic::Vector
2020-12-29 | perl v5.32.0 |