diff --git a/lib/node_modules/@stdlib/stats/incr/lib/index.js b/lib/node_modules/@stdlib/stats/incr/lib/index.js
index 8e95b0eca2ac..bbe5051bcd53 100644
--- a/lib/node_modules/@stdlib/stats/incr/lib/index.js
+++ b/lib/node_modules/@stdlib/stats/incr/lib/index.js
@@ -945,6 +945,15 @@ setReadOnly( ns, 'incrvmr', require( '@stdlib/stats/incr/vmr' ) );
*/
setReadOnly( ns, 'incrwmean', require( '@stdlib/stats/incr/wmean' ) );
+/**
+* @name incrwvariance
+* @memberof ns
+* @readonly
+* @type {Function}
+* @see {@link module:@stdlib/stats/incr/wvariance}
+*/
+setReadOnly( ns, 'incrwvariance', require( '@stdlib/stats/incr/wvariance' ) );
+
// EXPORTS //
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/README.md b/lib/node_modules/@stdlib/stats/incr/wvariance/README.md
new file mode 100644
index 000000000000..5864b7962c4f
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/README.md
@@ -0,0 +1,163 @@
+
+
+# incrwvariance
+
+> Compute a [weighted variance][weighted-variance] incrementally.
+
+
+
+The [weighted variance][weighted-variance] is defined as
+
+
+
+```math
+\sigma^2_w = \frac{\sum_{i=1}^N w_i (x_i - \mu_w)^2}{\sum_{i=1}^N w_i}
+```
+
+
+
+
+
+where `μ_w` is the weighted arithmetic mean.
+
+
+
+
+
+
+
+## Usage
+
+```javascript
+var incrwvariance = require( '@stdlib/stats/incr/wvariance' );
+```
+
+#### incrwvariance()
+
+Returns an accumulator `function` which incrementally computes a [weighted variance][weighted-variance].
+
+```javascript
+var accumulator = incrwvariance();
+```
+
+#### accumulator( \[x, w] )
+
+If provided an input value `x` and a weight `w`, the accumulator function returns an updated weighted variance. If not provided any input values, the accumulator function returns the current variance.
+
+```javascript
+var accumulator = incrwvariance();
+
+var s2 = accumulator( 2.0, 1.0 );
+// returns 0.0
+
+s2 = accumulator( 2.0, 0.5 );
+// returns 0.0
+
+s2 = accumulator( 3.0, 1.5 );
+// returns 0.25
+
+s2 = accumulator();
+// returns 0.25
+```
+
+
+
+
+
+
+
+## Notes
+
+- Input values are **not** type checked. If provided `NaN` or a value which, when used in computations, results in `NaN`, the accumulated value is `NaN` 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
+
+
+
+```javascript
+var randu = require( '@stdlib/random/base/randu' );
+var incrwvariance = require( '@stdlib/stats/incr/wvariance' );
+
+var accumulator;
+var v;
+var w;
+var i;
+
+// Initialize an accumulator:
+accumulator = incrwvariance();
+
+// For each simulated datum, update the weighted variance...
+for ( i = 0; i < 100; i++ ) {
+ v = randu() * 100.0;
+ w = randu() * 100.0;
+ accumulator( v, w );
+}
+console.log( accumulator() );
+```
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+[weighted-variance]: https://en.wikipedia.org/wiki/Weighted_arithmetic_mean#Weighted_sample_variance
+
+
+
+[@stdlib/stats/incr/ewvariance]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/stats/incr/ewvariance
+
+[@stdlib/stats/incr/variance]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/stats/incr/variance
+
+[@stdlib/stats/incr/wmean]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/stats/incr/wmean
+
+
+
+
+
+
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/benchmark/benchmark.js b/lib/node_modules/@stdlib/stats/incr/wvariance/benchmark/benchmark.js
new file mode 100644
index 000000000000..deead6f6a373
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/benchmark/benchmark.js
@@ -0,0 +1,70 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var bench = require( '@stdlib/bench' );
+var randu = require( '@stdlib/random/base/randu' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+var incrwvariance = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+ var f;
+ var i;
+ b.tic();
+ for ( i = 0; i < b.iterations; i++ ) {
+ f = incrwvariance();
+ if ( typeof f !== 'function' ) {
+ b.fail( 'should return a function' );
+ }
+ }
+ b.toc();
+ if ( typeof f !== 'function' ) {
+ b.fail( 'should return a function' );
+ }
+ b.pass( 'benchmark finished' );
+ b.end();
+});
+
+bench( format( '%s::accumulator', pkg ), function benchmark( b ) {
+ var acc;
+ var v;
+ var i;
+
+ acc = incrwvariance();
+
+ b.tic();
+ for ( i = 0; i < b.iterations; i++ ) {
+ v = acc( randu(), 1.0 );
+ if ( v !== v ) {
+ b.fail( 'should not return NaN' );
+ }
+ }
+ b.toc();
+ if ( v !== v ) {
+ b.fail( 'should not return NaN' );
+ }
+ b.pass( 'benchmark finished' );
+ b.end();
+});
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/docs/repl.txt b/lib/node_modules/@stdlib/stats/incr/wvariance/docs/repl.txt
new file mode 100644
index 000000000000..17476ddaed5d
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/docs/repl.txt
@@ -0,0 +1,39 @@
+
+{{alias}}()
+ Returns an accumulator function which incrementally computes a weighted
+ variance.
+
+ If provided arguments, the accumulator function returns an updated weighted
+ variance. If not provided arguments, the accumulator function returns the
+ current weighted variance.
+
+ If provided `NaN` or a value which, when used in computations, results in
+ `NaN`, the accumulated value is `NaN` for all future invocations.
+
+ The accumulator function accepts two arguments:
+
+ - x: value.
+ - w: weight.
+
+ Returns
+ -------
+ acc: Function
+ Accumulator function.
+
+ Examples
+ --------
+ > var accumulator = {{alias}}();
+ > var s2 = accumulator()
+ null
+ > s2 = accumulator( 2.0, 1.0 )
+ 0.0
+ > s2 = accumulator( 2.0, 0.5 )
+ 0.0
+ > s2 = accumulator( 3.0, 1.5 )
+ 0.25
+ > s2 = accumulator()
+ 0.25
+
+ See Also
+ --------
+
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/docs/types/index.d.ts b/lib/node_modules/@stdlib/stats/incr/wvariance/docs/types/index.d.ts
new file mode 100644
index 000000000000..5376c8b753fe
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/docs/types/index.d.ts
@@ -0,0 +1,64 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+// TypeScript Version: 4.1
+
+///
+
+/**
+* If provided both arguments, returns an updated weighted variance; otherwise, returns the current weighted variance.
+*
+* ## Notes
+*
+* - If provided `NaN` or a value which, when used in computations, results in `NaN`, the accumulated value is `NaN` for all future invocations.
+*
+* @param x - value
+* @param w - weight
+* @returns weighted variance
+*/
+type accumulator = ( x?: number, w?: number ) => number | null;
+
+/**
+* Returns an accumulator function which incrementally computes a weighted variance.
+*
+* @returns accumulator function
+*
+* @example
+* var accumulator = incrwvariance();
+*
+* var s2 = accumulator();
+* // returns null
+*
+* s2 = accumulator( 2.0, 1.0 );
+* // returns 0.0
+*
+* s2 = accumulator( 2.0, 0.5 );
+* // returns 0.0
+*
+* s2 = accumulator( 3.0, 1.5 );
+* // returns 0.25
+*
+* s2 = accumulator();
+* // returns 0.25
+*/
+declare function incrwvariance(): accumulator;
+
+
+// EXPORTS //
+
+export = incrwvariance;
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/docs/types/test.ts b/lib/node_modules/@stdlib/stats/incr/wvariance/docs/types/test.ts
new file mode 100644
index 000000000000..bd13b52e61cd
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/docs/types/test.ts
@@ -0,0 +1,69 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+import incrwvariance = require( './index' );
+
+
+// TESTS //
+
+// The function returns an accumulator function...
+{
+ incrwvariance(); // $ExpectType accumulator
+}
+
+// The compiler throws an error if the function is provided arguments...
+{
+ incrwvariance( '5' ); // $ExpectError
+ incrwvariance( 5 ); // $ExpectError
+ incrwvariance( true ); // $ExpectError
+ incrwvariance( false ); // $ExpectError
+ incrwvariance( null ); // $ExpectError
+ incrwvariance( undefined ); // $ExpectError
+ incrwvariance( [] ); // $ExpectError
+ incrwvariance( {} ); // $ExpectError
+ incrwvariance( ( x: number ): number => x ); // $ExpectError
+}
+
+// The function returns an accumulator function which returns an accumulated result...
+{
+ const acc = incrwvariance();
+
+ acc(); // $ExpectType number | null
+ acc( 3.14, 1.0 ); // $ExpectType number | null
+}
+
+// The compiler throws an error if the returned accumulator function is provided invalid arguments...
+{
+ const acc = incrwvariance();
+
+ acc( '5', 1.0 ); // $ExpectError
+ acc( true, 1.0 ); // $ExpectError
+ acc( false, 1.0 ); // $ExpectError
+ acc( null, 1.0 ); // $ExpectError
+ acc( [], 1.0 ); // $ExpectError
+ acc( {}, 1.0 ); // $ExpectError
+ acc( ( x: number ): number => x, 1.0 ); // $ExpectError
+
+ acc( 3.14, '5' ); // $ExpectError
+ acc( 3.14, true ); // $ExpectError
+ acc( 3.14, false ); // $ExpectError
+ acc( 3.14, null ); // $ExpectError
+ acc( 3.14, [] ); // $ExpectError
+ acc( 3.14, {} ); // $ExpectError
+ acc( 3.14, ( x: number ): number => x ); // $ExpectError
+}
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/examples/index.js b/lib/node_modules/@stdlib/stats/incr/wvariance/examples/index.js
new file mode 100644
index 000000000000..9783b4e28891
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/examples/index.js
@@ -0,0 +1,41 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+var randu = require( '@stdlib/random/base/randu' );
+var incrwvariance = require( './../lib' );
+
+var accumulator;
+var s2;
+var x;
+var w;
+var i;
+
+// Initialize an accumulator:
+accumulator = incrwvariance();
+
+// For each simulated datum, update the weighted variance...
+console.log( '\nValue\tWeight\tWeighted Variance\n' );
+for ( i = 0; i < 100; i++ ) {
+ x = randu() * 100.0;
+ w = randu() * 100.0;
+ s2 = accumulator( x, w );
+ console.log( '%d\t%d\t%d', x.toFixed( 4 ), w.toFixed( 4 ), s2.toFixed( 4 ) );
+}
+console.log( '\nFinal weighted variance: %d\n', accumulator() );
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/lib/index.js b/lib/node_modules/@stdlib/stats/incr/wvariance/lib/index.js
new file mode 100644
index 000000000000..cd7cf749f9da
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/lib/index.js
@@ -0,0 +1,54 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+/**
+* Compute a weighted variance incrementally.
+*
+* @module @stdlib/stats/incr/wvariance
+*
+* @example
+* var incrwvariance = require( '@stdlib/stats/incr/wvariance' );
+*
+* var accumulator = incrwvariance();
+*
+* var s2 = accumulator();
+* // returns null
+*
+* s2 = accumulator( 2.0, 1.0 );
+* // returns 0.0
+*
+* s2 = accumulator( 2.0, 0.5 );
+* // returns 0.0
+*
+* s2 = accumulator( 3.0, 1.5 );
+* // returns 0.25
+*
+* s2 = accumulator();
+* // returns 0.25
+*/
+
+// MODULES //
+
+var main = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = main;
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/lib/main.js b/lib/node_modules/@stdlib/stats/incr/wvariance/lib/main.js
new file mode 100644
index 000000000000..53d012ca3a34
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/lib/main.js
@@ -0,0 +1,148 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+
+/**
+* Returns an accumulator function which incrementally computes a weighted variance.
+*
+* ## Method
+*
+* - The weighted variance is defined as
+*
+* ```tex
+* \sigma_w^2 = \frac{\sum_{i=1}^{n} w_i (x_i - \mu_w)^2}{\sum_{i=1}^{n} w_i}
+* ```
+*
+* where \\( \mu_w \\) is the weighted arithmetic mean.
+*
+* - Define the total weight
+*
+* ```tex
+* W_n = \sum_{i=1}^{n} w_i
+* ```
+*
+* - Define the unnormalized second central moment
+*
+* ```tex
+* S_n = \sum_{i=1}^{n} w_i (x_i - \mu_n)^2
+* ```
+*
+* - The weighted variance is obtained by normalizing
+*
+* ```tex
+* \sigma_n^2 = \frac{S_n}{W_n}
+* ```
+*
+* - The weighted mean is updated incrementally according to
+*
+* ```tex
+* \mu_n = \mu_{n-1} + \frac{w_n}{W_n}(x_n - \mu_{n-1})
+* ```
+*
+* - Using this update, the unnormalized variance accumulator satisfies
+*
+* ```tex
+* S_n = S_{n-1} + w_n (x_n - \mu_{n-1})(x_n - \mu_n)
+* ```
+*
+* which yields a numerically stable, one-pass algorithm for computing the
+* weighted variance.
+*
+* @returns {Function} accumulator function
+*
+* @example
+* var accumulator = incrwvariance();
+*
+* var s2 = accumulator();
+* // returns null
+*
+* s2 = accumulator( 2.0, 1.0 );
+* // returns 0.0
+*
+* s2 = accumulator( 2.0, 0.5 );
+* // returns 0.0
+*
+* s2 = accumulator( 3.0, 1.5 );
+* // returns 0.25
+*
+* s2 = accumulator();
+* // returns 0.25
+*/
+function incrwvariance() {
+ var poisoned;
+ var mu;
+ var W;
+ var S;
+ var N;
+
+ N = 0;
+ W = 0.0;
+ S = 0.0;
+ mu = 0.0;
+ poisoned = false;
+
+ return accumulator;
+
+ /**
+ * If provided arguments, the accumulator function returns an updated weighted variance. If not provided arguments, the accumulator function returns the current weighted variance.
+ *
+ * @private
+ * @param {number} [x] - value
+ * @param {number} [w] - weight
+ * @returns {(number|null)} weighted variance or null
+ */
+ function accumulator( x, w ) {
+ var muprev;
+ if ( poisoned ) {
+ return NaN;
+ }
+
+ if ( arguments.length === 0 ) {
+ if ( N === 0 ) {
+ return null;
+ }
+ return S / W;
+ }
+ if ( arguments.length !== 2 ) {
+ poisoned = true;
+ return NaN;
+ }
+ if ( isnan( x ) || isnan( w ) ) {
+ poisoned = true;
+ return NaN;
+ }
+
+ N += 1;
+ W += w;
+ muprev = mu;
+ mu += ( w / W ) * ( x - mu );
+ S += w * ( x - muprev ) * ( x - mu );
+ if ( N === 1 ) {
+ return 0.0;
+ }
+ return S / W;
+ }
+}
+
+
+// EXPORTS //
+
+module.exports = incrwvariance;
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/package.json b/lib/node_modules/@stdlib/stats/incr/wvariance/package.json
new file mode 100644
index 000000000000..3c3731d82e31
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/package.json
@@ -0,0 +1,64 @@
+{
+ "name": "@stdlib/stats/incr/wvariance",
+ "version": "0.0.0",
+ "description": "Compute a weighted variance incrementally.",
+ "license": "Apache-2.0",
+ "author": {
+ "name": "The Stdlib Authors",
+ "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+ },
+ "contributors": [
+ {
+ "name": "The Stdlib Authors",
+ "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+ }
+ ],
+ "main": "./lib",
+ "directories": {
+ "benchmark": "./benchmark",
+ "doc": "./docs",
+ "example": "./examples",
+ "lib": "./lib",
+ "test": "./test"
+ },
+ "types": "./docs/types",
+ "scripts": {},
+ "homepage": "https://github.com/stdlib-js/stdlib",
+ "repository": {
+ "type": "git",
+ "url": "git://github.com/stdlib-js/stdlib.git"
+ },
+ "bugs": {
+ "url": "https://github.com/stdlib-js/stdlib/issues"
+ },
+ "dependencies": {},
+ "devDependencies": {},
+ "engines": {
+ "node": ">=0.10.0",
+ "npm": ">2.7.0"
+ },
+ "os": [
+ "aix",
+ "darwin",
+ "freebsd",
+ "linux",
+ "macos",
+ "openbsd",
+ "sunos",
+ "win32",
+ "windows"
+ ],
+ "keywords": [
+ "stdlib",
+ "stdmath",
+ "statistics",
+ "stats",
+ "mathematics",
+ "math",
+ "variance",
+ "dispersion",
+ "incremental",
+ "accumulator",
+ "weighted"
+ ]
+}
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/test/fixtures/python/data.json b/lib/node_modules/@stdlib/stats/incr/wvariance/test/fixtures/python/data.json
new file mode 100644
index 000000000000..b564128515de
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/test/fixtures/python/data.json
@@ -0,0 +1,302 @@
+[
+ {
+ "step": 1,
+ "x": 3.0471707975443136,
+ "w": 3.9559294497604784,
+ "variance": 0.0
+ },
+ {
+ "step": 2,
+ "x": -10.399841062404956,
+ "w": 3.3577691973009576,
+ "variance": 44.90315233839998
+ },
+ {
+ "step": 3,
+ "x": 7.5045119580645725,
+ "w": 3.555310355269042,
+ "variance": 55.09102587431526
+ },
+ {
+ "step": 4,
+ "x": 9.405647163912139,
+ "w": 3.925572252007643,
+ "variance": 56.455245135800695
+ },
+ {
+ "step": 5,
+ "x": -19.510351886538363,
+ "w": 2.348687300137866,
+ "variance": 107.32680173840433
+ },
+ {
+ "step": 6,
+ "x": -13.021795068623181,
+ "w": 2.88683186016918,
+ "variance": 111.8326745713744
+ },
+ {
+ "step": 7,
+ "x": 1.2784040316728538,
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+ "variance": 104.75088093868614
+ },
+ {
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+ "variance": 90.93461372403924
+ },
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+ "variance": 86.56665456148613
+ },
+ {
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+ "variance": 89.08091132804846
+ },
+ {
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+ "variance": 87.2966151572343
+ },
+ {
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+ "variance": 79.83165903313335
+ },
+ {
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+ "variance": 82.82814070104052
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+ },
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+ "variance": 78.65087778992203
+ },
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+ },
+ {
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+ },
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+ },
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+ "variance": 59.820142017832474
+ },
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+ "variance": 57.75725279503625
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+ "variance": 65.90674094211543
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+ {
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+ "w": 0.6782289203905251,
+ "variance": 65.79701293549093
+ },
+ {
+ "step": 48,
+ "x": 2.2359554877468226,
+ "w": 4.813298556292621,
+ "variance": 62.95703448849857
+ },
+ {
+ "step": 49,
+ "x": 6.789135630718949,
+ "w": 4.552045384467275,
+ "variance": 61.42895867146031
+ },
+ {
+ "step": 50,
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+ "w": 3.5285649556726733,
+ "variance": 59.659440510098804
+ }
+]
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/test/fixtures/python/runner.py b/lib/node_modules/@stdlib/stats/incr/wvariance/test/fixtures/python/runner.py
new file mode 100644
index 000000000000..f2c5b3b141d4
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/test/fixtures/python/runner.py
@@ -0,0 +1,55 @@
+#!/usr/bin/env python
+#
+# @license Apache-2.0
+#
+# Copyright (c) 2026 The Stdlib Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+"""Generate fixture data for testing incremental weighted variance."""
+
+import json
+import numpy as np
+
+# reproducibility
+rng = np.random.default_rng(42)
+
+n = 50 # number of samples
+
+# generate data
+x = rng.normal(loc=0.0, scale=10.0, size=n)
+w = rng.uniform(0.1, 5.0, size=n)
+
+records = []
+
+for k in range(1, n + 1):
+ xk = x[:k]
+ wk = w[:k]
+
+ mu = np.average(xk, weights=wk)
+
+ var = np.average((xk - mu) ** 2, weights=wk)
+
+ records.append({
+ "step": k,
+ "x": float(x[k - 1]),
+ "w": float(w[k - 1]),
+ "variance": float(var)
+ })
+
+# write to json
+with open("data.json", "w", encoding="utf-8") as f:
+ json.dump(records, f, indent=2)
+
+print("data.json written with", n, "records")
diff --git a/lib/node_modules/@stdlib/stats/incr/wvariance/test/test.js b/lib/node_modules/@stdlib/stats/incr/wvariance/test/test.js
new file mode 100644
index 000000000000..d581b52a0dd4
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/wvariance/test/test.js
@@ -0,0 +1,98 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var tape = require( 'tape' );
+var isAlmostSameValue = require( '@stdlib/assert/is-almost-same-value' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var data = require( './fixtures/python/data.json' );
+var incrwvariance = require( './../lib' );
+
+
+// TESTS //
+
+tape( 'main export is a function', function test( t ) {
+ t.ok( true, __filename );
+ t.strictEqual( typeof incrwvariance, 'function', 'main export is a function' );
+ t.end();
+});
+
+tape( 'the function returns an accumulator function', function test( t ) {
+ t.strictEqual( typeof incrwvariance(), 'function', 'returns expected value' );
+ t.end();
+});
+
+tape( 'the initial accumulated value is `null`', function test( t ) {
+ var acc = incrwvariance();
+ t.strictEqual( acc(), null, 'returns expected value' );
+ t.end();
+});
+
+tape( 'the accumulator function incrementally computes a weighted variance', function test( t ) {
+ var expected;
+ var actual;
+ var acc;
+ var i;
+
+ acc = incrwvariance();
+
+ for ( i = 0; i < data.length; i++ ) {
+ expected = data[ i ].variance;
+ actual = acc( data[ i ].x, data[ i ].w );
+ t.strictEqual( isAlmostSameValue( actual, expected, 40.0 ), true, 'within tolerance. x: ' + data[i].x + '. w: ' + data[i].w + '. Value: ' + actual + '. Expected: ' + expected + '.' );
+ }
+ t.end();
+});
+
+tape( 'if not provided arguments, the accumulator function returns the current weighted variance', function test( t ) {
+ var expected = data[ data.length - 1 ].variance;
+ var acc;
+ var i;
+
+ acc = incrwvariance();
+ for ( i = 0; i < data.length; i++ ) {
+ acc( data[ i ].x, data[ i ].w );
+ }
+ t.strictEqual( isAlmostSameValue( acc(), expected, 40.0 ), true, 'returns expected value' );
+ t.end();
+});
+
+tape( 'if not provided a weight, the accumulator function returns `NaN`', function test( t ) {
+ var acc = incrwvariance();
+ t.strictEqual( isnan( acc( 2.0 ) ), true, 'returns expected value' );
+ t.strictEqual( isnan( acc( 3.14 ) ), true, 'returns expected value' );
+ t.end();
+});
+
+tape( 'if provided `NaN` for either a value or a weight, the accumulator function returns `NaN`', function test( t ) {
+ var acc = incrwvariance();
+ t.strictEqual( isnan( acc( 2.0, NaN ) ), true, 'returns expected value' );
+ t.strictEqual( isnan( acc( 3.14, NaN ) ), true, 'returns expected value' );
+
+ acc = incrwvariance();
+ t.strictEqual( isnan( acc( NaN, 1.0 ) ), true, 'returns expected value' );
+ t.strictEqual( isnan( acc( NaN, 1.0 ) ), true, 'returns expected value' );
+
+ acc = incrwvariance();
+ t.strictEqual( isnan( acc( NaN, NaN ) ), true, 'returns expected value' );
+ t.strictEqual( isnan( acc( NaN, NaN ) ), true, 'returns expected value' );
+ t.end();
+});