chore: fix readme tests

Author: aayush0325

lib/node_modules/@stdlib/stats/base/dnanmeanpw/README.md

@@ -77,7 +77,7 @@ var Float64Array = require( '@stdlib/array/float64' );
 
 var x = new Float64Array( [ 1.0, 2.0, 2.0, -7.0, -2.0, 3.0, 4.0, 2.0, NaN ] );
 
-var v = dnanmeanpw( 4, x, 2 );
+var v = dnanmeanpw( 5, x, 2 );
 // returns 1.25
 ```