Provided by: libstatistics-basic-perl_1.6611-1_all #### NAME

```       Statistics::Basic::StdDev - find the standard deviation of a list

```

#### SYNOPSIS

```       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;
}

```

#### 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::StdDev
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 standard deviation computation.

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

```

```       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).

```

#### 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.

```

```       Copyright 2012 Paul Miller -- Licensed under the LGPL
```       perl(1), Statistics::Basic, Statistics::Basic::_OneVectorBase, Statistics::Basic::Vector