diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/README.md b/lib/node_modules/@stdlib/stats/incr/nanwmean/README.md
new file mode 100644
index 000000000000..329921e50faf
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/README.md
@@ -0,0 +1,152 @@
+
+
+# incrnanwmean
+
+> Compute a [weighted arithmetic mean][weighted-arithmetic-mean] incrementally, ignoring `NaN` values.
+
+
+
+The [weighted arithmetic mean][weighted-arithmetic-mean] is defined as
+
+
+
+```math
+\bar{x} = \frac{\displaystyle\sum_{i=0}^{n-1} w_{i} x_{i}}{\displaystyle\sum_{i=0}^{n-1} w_{i}}
+```
+
+
+
+
+
+
+
+
+
+
+
+## Usage
+
+```javascript
+var incrnanwmean = require( '@stdlib/stats/incr/nanwmean' );
+```
+
+#### incrnanwmean()
+
+Returns an accumulator `function` which incrementally computes a [weighted arithmetic mean][weighted-arithmetic-mean], ignoring NaN values.
+
+```javascript
+var accumulator = incrnanwmean();
+```
+
+#### accumulator( \[x, w] )
+
+If provided an input value `x` and a weight `w`, the accumulator function returns an updated weighted mean. If not provided any input values, the accumulator function returns the current mean.
+
+```javascript
+var accumulator = incrnanwmean();
+
+var mu = accumulator( 2.0, 1.0 );
+// returns 2.0
+
+mu = accumulator( 2.0, 0.5 );
+// returns 2.0
+
+mu = accumulator( 3.0, 1.5 );
+// returns 2.5
+
+mu = accumulator();
+// returns 2.5
+
+mu = accumulator( NaN, 2 );
+// returns 2.5
+
+mu = accumulator( 2, NaN );
+// returns 2.5
+
+mu = accumulator( NaN, NaN );
+// returns 2.5
+```
+
+
+
+
+
+
+
+
+
+
+
+
+
+## Examples
+
+
+
+```javascript
+var randu = require( '@stdlib/random/base/randu' );
+var incrnanwmean = require( '@stdlib/stats/incr/nanwmean' );
+
+var accumulator;
+var mean;
+var v;
+var w;
+var i;
+
+accumulator = incrnanwmean();
+
+for ( i = 0; i < 100; i++ ) {
+ if ( randu() < 0.2 ) {
+ v = NaN;
+ w = NaN;
+ } else {
+ v = randu() * 100.0;
+ w = randu() * 10.0;
+ }
+ accumulator( v, w );
+}
+console.log( accumulator() );
+```
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+[weighted-arithmetic-mean]: https://en.wikipedia.org/wiki/Weighted_arithmetic_mean
+
+
+
+
diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/benchmark/benchmark.js b/lib/node_modules/@stdlib/stats/incr/nanwmean/benchmark/benchmark.js
new file mode 100644
index 000000000000..174c66f7bc74
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/benchmark/benchmark.js
@@ -0,0 +1,66 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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 pkg = require( './../package.json' ).name;
+var incrnanwmean = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+ var f;
+ var i;
+ b.tic();
+ for ( i = 0; i < b.iterations; i++ ) {
+ f = incrnanwmean();
+ 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( pkg+'::accumulator', function benchmark( b ) {
+ var acc;
+ var v;
+ var w;
+ var i;
+
+ acc = incrnanwmean();
+
+ b.tic();
+ for ( i = 0; i < b.iterations; i++ ) {
+ v = ( randu() < 0.2 ) ? NaN : randu() * 100.0;
+ w = ( randu() < 0.2 ) ? NaN : randu() * 10.0;
+ acc( v, w );
+ }
+ b.toc();
+ b.pass( 'benchmark finished' );
+ b.end();
+});
diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/img/equation_weighted_arithmetic_mean.svg b/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/img/equation_weighted_arithmetic_mean.svg
new file mode 100644
index 000000000000..28531390be9c
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/img/equation_weighted_arithmetic_mean.svg
@@ -0,0 +1,63 @@
+
\ No newline at end of file
diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/repl.txt b/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/repl.txt
new file mode 100644
index 000000000000..b1e9037b6697
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/repl.txt
@@ -0,0 +1,41 @@
+{{alias}}()
+ Returns an accumulator function which incrementally computes a weighted
+ arithmetic mean, ignoring `NaN` values.
+
+ If provided arguments, the accumulator function returns an updated weighted
+ mean. If not provided arguments, the accumulator function returns the
+ current weighted mean.
+
+ If provided `NaN` for either a value or a weight, the accumulated value
+ remains unchanged and does not include the `NaN` values in computations.
+
+ The accumulator function accepts two arguments:
+
+ - x: value.
+ - w: weight.
+
+ Returns
+ -------
+ acc: Function
+ Accumulator function.
+
+ Examples
+ --------
+ > var accumulator = {{alias}}();
+ > var mu = accumulator()
+ null
+ > mu = accumulator( 2.0, 1.0 )
+ 2.0
+ > mu = accumulator( NaN, 1.0 )
+ 2.0
+ > mu = accumulator( 3.0, 2.0 )
+ 2.6666666666666665
+ > mu = accumulator( 4.0, NaN )
+ 2.6666666666666665
+ > mu = accumulator( 5.0, 3.0 )
+ 3.833333333333333
+ > mu = accumulator()
+ 3.833333333333333
+
+ See Also
+ --------
diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/types/index.d.ts b/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/types/index.d.ts
new file mode 100644
index 000000000000..ae26ac2e452f
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/types/index.d.ts
@@ -0,0 +1,63 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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 values, returns an updated weighted mean; otherwise, returns the current weighted mean.
+*
+* @param x - value
+* @param w - weight
+* @returns weighted mean
+*/
+type accumulator = ( x?: number, w?: number ) => number | null;
+
+/**
+* Returns an accumulator function which incrementally computes a weighted mean, ignoring `NaN` values.
+*
+* @returns accumulator function
+*
+* @example
+* var accumulator = incrnanwmean();
+*
+* var v = accumulator();
+* // returns null
+*
+* v = accumulator( 2.0, 1.0 );
+* // returns 2.0
+*
+* v = accumulator( 3.0, 2.0 );
+* // returns 2.666...
+*
+* v = accumulator( NaN, 1.0 );
+* // returns 2.666...
+*
+* v = accumulator( 4.0, 3.0 );
+* // returns 3.166...
+*
+* v = accumulator();
+* // returns 3.166...
+*/
+declare function incrnanwmean(): accumulator;
+
+
+// EXPORTS //
+
+export = incrnanwmean;
diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/types/test.ts b/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/types/test.ts
new file mode 100644
index 000000000000..cd62121c2923
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/docs/types/test.ts
@@ -0,0 +1,66 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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 incrnanwmean = require( './index' );
+
+
+// TESTS //
+
+// The function returns an accumulator function...
+{
+ incrnanwmean(); // $ExpectType accumulator
+}
+
+// The compiler throws an error if the function is provided arguments...
+{
+ incrnanwmean( '5' ); // $ExpectError
+ incrnanwmean( 5 ); // $ExpectError
+ incrnanwmean( true ); // $ExpectError
+ incrnanwmean( false ); // $ExpectError
+ incrnanwmean( null ); // $ExpectError
+ incrnanwmean( undefined ); // $ExpectError
+ incrnanwmean( [] ); // $ExpectError
+ incrnanwmean( {} ); // $ExpectError
+ incrnanwmean( ( x: number ): number => x ); // $ExpectError
+}
+
+// The function returns an accumulator function which returns an accumulated result...
+{
+ const acc = incrnanwmean();
+
+ acc(); // $ExpectType number | null
+ acc( 3.14, 2.0 ); // $ExpectType number | null
+}
+
+// The compiler throws an error if the returned accumulator function is provided invalid arguments...
+{
+ const acc = incrnanwmean();
+
+ acc( '5', 1.0 ); // $ExpectError
+ acc( 3.14, '2' ); // $ExpectError
+ acc( true, 2.0 ); // $ExpectError
+ acc( 3.14, false ); // $ExpectError
+ acc( null, 1.0 ); // $ExpectError
+ acc( 3.14, null ); // $ExpectError
+ acc( [], 1.0 ); // $ExpectError
+ acc( 3.14, [] ); // $ExpectError
+ acc( {}, 1.0 ); // $ExpectError
+ acc( 3.14, {} ); // $ExpectError
+ acc( ( x: number ): number => x, 1.0 ); // $ExpectError
+ acc( 3.14, ( x: number ): number => x ); // $ExpectError
+}
diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/examples/index.js b/lib/node_modules/@stdlib/stats/incr/nanwmean/examples/index.js
new file mode 100644
index 000000000000..922a9f7963a5
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/examples/index.js
@@ -0,0 +1,44 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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 incrnanwmean = require( './../lib' );
+
+var accumulator;
+var mean;
+var v;
+var w;
+var i;
+
+accumulator = incrnanwmean();
+
+console.log( '\nValue\tWeight\tMean\n' );
+for ( i = 0; i < 100; i++ ) {
+ if ( randu() < 0.2 ) {
+ v = NaN;
+ w = NaN;
+ } else {
+ v = randu() * 100.0;
+ w = randu() * 10.0;
+ }
+ mean = accumulator( v, w );
+ console.log( '%d\t%d\t%d', v.toFixed( 4 ), w.toFixed( 4 ), ( mean === null ) ? NaN : mean.toFixed( 4 ) );
+}
+console.log( '\nFinal weighted mean: %d\n', accumulator() );
diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/lib/index.js b/lib/node_modules/@stdlib/stats/incr/nanwmean/lib/index.js
new file mode 100644
index 000000000000..8f9572736c75
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/lib/index.js
@@ -0,0 +1,54 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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 mean incrementally, ignoring `NaN` values.
+*
+* @module @stdlib/stats/incr/nanwmean
+*
+* @example
+* var incrnanwmean = require( '@stdlib/stats/incr/nanwmean' );
+*
+* var accumulator = incrnanwmean();
+*
+* var mean = accumulator();
+* // returns null
+*
+* mean = accumulator( 2.0, 1.0 );
+* // returns 2.0
+*
+* mean = accumulator( NaN, 1.0 );
+* // returns 2.0
+*
+* mean = accumulator( -5.0, 2.0 );
+* // returns -2.0
+*
+* mean = accumulator();
+* // returns -2.0
+*/
+
+// MODULES //
+
+var main = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = main;
diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/lib/main.js b/lib/node_modules/@stdlib/stats/incr/nanwmean/lib/main.js
new file mode 100644
index 000000000000..96d82b0350f5
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/lib/main.js
@@ -0,0 +1,75 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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 isnan = require( '@stdlib/math/base/assert/is-nan' );
+var incrwmean = require( '@stdlib/stats/incr/wmean' );
+
+
+// MAIN //
+
+/**
+* Returns an accumulator function which incrementally computes a weighted mean, ignoring `NaN` values.
+*
+* @returns {Function} accumulator function
+*
+* @example
+* var accumulator = incrnanwmean();
+*
+* var mean = accumulator();
+* // returns null
+*
+* mean = accumulator( 2.0, 1.0 );
+* // returns 2.0
+*
+* mean = accumulator( NaN, 1.0 );
+* // returns 2.0
+*
+* mean = accumulator( -5.0, 2.0 );
+* // returns -2.666666666666666
+*
+* mean = accumulator();
+* // returns -2.666666666666666
+*/
+function incrnanwmean() {
+ var wmean = incrwmean();
+ return accumulator;
+
+ /**
+ * If provided arguments, the accumulator function returns an updated weighted mean. If not provided arguments, the accumulator function returns the current weighted mean.
+ *
+ * @private
+ * @param {number} [x] - value
+ * @param {number} [w] - weight
+ * @returns {(number|null)} weighted mean or null
+ */
+ function accumulator( x, w ) {
+ if ( arguments.length === 0 || isnan( x ) || isnan( w ) ) {
+ return wmean();
+ }
+ return wmean( x, w );
+ }
+}
+
+
+// EXPORTS //
+
+module.exports = incrnanwmean;
diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/package.json b/lib/node_modules/@stdlib/stats/incr/nanwmean/package.json
new file mode 100644
index 000000000000..ccf2c2737bf7
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/package.json
@@ -0,0 +1,70 @@
+{
+ "name": "@stdlib/stats/incr/nanwmean",
+ "version": "0.0.0",
+ "description": "Compute a weighted arithmetic mean incrementally, ignoring NaN values.",
+ "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",
+ "average",
+ "avg",
+ "mean",
+ "arithmetic mean",
+ "central tendency",
+ "incremental",
+ "accumulator",
+ "weighted mean",
+ "nan",
+ "ignore nan"
+ ]
+}
+
diff --git a/lib/node_modules/@stdlib/stats/incr/nanwmean/test/test.js b/lib/node_modules/@stdlib/stats/incr/nanwmean/test/test.js
new file mode 100644
index 000000000000..b29b28853509
--- /dev/null
+++ b/lib/node_modules/@stdlib/stats/incr/nanwmean/test/test.js
@@ -0,0 +1,138 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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 isnan = require( '@stdlib/math/base/assert/is-nan' );
+var EPS = require( '@stdlib/constants/float64/eps' );
+var abs = require( '@stdlib/math/base/special/abs' );
+var incrnanwmean = require( './../lib' );
+
+
+// TESTS //
+
+tape( 'main export is a function', function test( t ) {
+ t.ok( true, __filename );
+ t.strictEqual( typeof incrnanwmean, 'function', 'main export is a function' );
+ t.end();
+});
+
+tape( 'the function returns an accumulator function', function test( t ) {
+ t.strictEqual( typeof incrnanwmean(), 'function', 'returns a function' );
+ t.end();
+});
+
+tape( 'the initial accumulated value is `null`', function test( t ) {
+ var acc = incrnanwmean();
+ t.equal( acc(), null, 'returns expected value' );
+ t.end();
+});
+
+tape( 'the accumulator function incrementally computes a weighted arithmetic mean, ignoring NaN values', function test( t ) {
+ var expected;
+ var actual;
+ var delta;
+ var dataX;
+ var dataW;
+ var xwSum;
+ var wSum;
+ var acc;
+ var tol;
+ var N;
+ var x;
+ var w;
+ var i;
+
+ dataX = [ 2.0, NaN, 3.0, NaN, 2.0, 4.0, NaN, 3.0, 4.0 ];
+ dataW = [ 1.0, 2.0, 2.0, NaN, 0.1, 1.8, 9.9, 3.6, NaN ];
+ N = dataX.length;
+
+ acc = incrnanwmean();
+
+ xwSum = 0.0;
+ wSum = 0.0;
+ for ( i = 0; i < N; i++ ) {
+ x = dataX[ i ];
+ w = dataW[ i ];
+
+ if ( !isnan( x ) && !isnan( w ) ) {
+ xwSum += x * w;
+ wSum += w;
+ }
+
+ expected = ( wSum === 0 ) ? null : xwSum / wSum;
+ actual = acc( x, w );
+
+ if ( expected === null ) {
+ t.equal( actual, null, 'returns expected null' );
+ } else {
+ delta = abs( actual - expected );
+ tol = EPS * abs( expected );
+ t.ok( delta <= tol, 'within tolerance. x: ' + x + '. w: ' + w + '. Value: ' + actual + '. Expected: ' + expected + '. Tolerance: ' + tol + '.' );
+ }
+ }
+ t.end();
+});
+
+tape( 'if not provided arguments, the accumulator function returns the current weighted mean', function test( t ) {
+ var dataX;
+ var dataW;
+ var acc;
+ var i;
+
+ dataX = [ 2.0, 3.0, 1.0 ];
+ dataW = [ 2.0, 2.0, 1.0 ];
+ acc = incrnanwmean();
+ for ( i = 0; i < dataX.length; i++ ) {
+ acc( dataX[ i ], dataW[ i ] );
+ }
+ t.equal( acc(), 2.2, 'returns the current accumulated mean' );
+ t.end();
+});
+
+tape( 'if provided only `NaN` values, the accumulator function does not update the mean', function test( t ) {
+ var acc = incrnanwmean();
+ acc( 10, 2 );
+ acc( NaN, NaN );
+ acc( NaN, 3 );
+ acc( 5, NaN );
+
+ t.equal( acc(), 10, 'ignores NaN inputs and keeps the previous mean' );
+ t.end();
+});
+
+tape( 'if no valid weights are provided, the accumulator returns `null`', function test( t ) {
+ var acc = incrnanwmean();
+ acc( NaN, NaN );
+ acc( NaN, NaN );
+ t.equal( acc(), null, 'returns null when no valid weights are given' );
+ t.end();
+});
+
+tape( 'if provided `NaN` for either a value or a weight, the accumulator function ignores the input', function test( t ) {
+ var acc = incrnanwmean();
+ acc( 2.0, 1.0 );
+ acc( NaN, 3.0 );
+ acc( 3.0, NaN );
+
+ t.equal( acc(), 2.0, 'ignores invalid inputs and maintains correct mean' );
+ t.end();
+});