@stdlib/stats-incr-stdev
v0.2.2
Published
Compute a corrected sample standard deviation incrementally.
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incrstdev
Compute a corrected sample standard deviation incrementally.
The corrected sample standard deviation is defined as
Installation
npm install @stdlib/stats-incr-stdev
Usage
var incrstdev = require( '@stdlib/stats-incr-stdev' );
incrstdev( [mean] )
Returns an accumulator function
which incrementally computes a corrected sample standard deviation.
var accumulator = incrstdev();
If the mean is already known, provide a mean
argument.
var accumulator = incrstdev( 3.0 );
accumulator( [x] )
If provided an input value x
, the accumulator function returns an updated corrected sample standard deviation. If not provided an input value x
, the accumulator function returns the current corrected sample standard deviation.
var accumulator = incrstdev();
var s = accumulator( 2.0 );
// returns 0.0
s = accumulator( 1.0 ); // => sqrt(((2-1.5)^2+(1-1.5)^2) / (2-1))
// returns ~0.7071
s = accumulator( 3.0 ); // => sqrt(((2-2)^2+(1-2)^2+(3-2)^2) / (3-1))
// returns 1.0
s = accumulator();
// returns 1.0
Notes
- Input values are not type checked. If provided
NaN
or a value which, when used in computations, results inNaN
, the accumulated value isNaN
for all future invocations. If non-numeric inputs are possible, you are advised to type check and handle accordingly before passing the value to the accumulator function.
Examples
var randu = require( '@stdlib/random-base-randu' );
var incrstdev = require( '@stdlib/stats-incr-stdev' );
var accumulator;
var v;
var i;
// Initialize an accumulator:
accumulator = incrstdev();
// For each simulated datum, update the sample standard deviation...
for ( i = 0; i < 100; i++ ) {
v = randu() * 100.0;
accumulator( v );
}
console.log( accumulator() );
See Also
@stdlib/stats-incr/kurtosis
: compute a corrected sample excess kurtosis incrementally.@stdlib/stats-incr/mean
: compute an arithmetic mean incrementally.@stdlib/stats-incr/mstdev
: compute a moving corrected sample standard deviation incrementally.@stdlib/stats-incr/skewness
: compute a corrected sample skewness incrementally.@stdlib/stats-incr/summary
: compute a statistical summary incrementally.@stdlib/stats-incr/variance
: compute an unbiased sample variance incrementally.
Notice
This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.