Refactor to use update formula using the residual and rename variable

Author: kgryte

lib/node_modules/@stdlib/stats/incr/ewmean/lib/main.js

@@ -49,7 +49,7 @@ var isNonNegativeNumber = require( '@stdlib/assert/is-nonnegative-number' ).isPr
 * // returns -1.5
 */
 function increwmean( alpha ) {
-	var v;
+	var m;
 	if ( !isNonNegativeNumber( alpha ) ) {
 		throw new TypeError( 'invalid input argument. Must provide a nonnegative number. Value: `' + alpha + '`.' );
 	}
@@ -67,14 +67,14 @@ function increwmean( alpha ) {
 	*/
 	function accumulator( x ) {
 		if ( arguments.length === 0 ) {
-			return ( v === void 0 ) ? null : v;
+			return ( m === void 0 ) ? null : m;
 		}
-		if ( v === void 0 ) {
-			v = x;
+		if ( m === void 0 ) {
+			m = x;
 		} else {
-			v = (alpha*x) + ((1.0-alpha)*v);
+			m += alpha * ( x-m );
 		}
-		return v;
+		return m;
 	}
 }