diff --git a/lib/accessor.js b/lib/accessor.js
index 7b6d9fb..f94c319 100644
--- a/lib/accessor.js
+++ b/lib/accessor.js
@@ -1,6 +1,6 @@
 'use strict';
 
-// FUNCTIONS
+// MODULES //
 
 var ERFCINV = require( './number.js' );
 
diff --git a/lib/deepset.js b/lib/deepset.js
index d22000b..89396a0 100644
--- a/lib/deepset.js
+++ b/lib/deepset.js
@@ -16,7 +16,7 @@ var deepSet = require( 'utils-deep-set' ).factory,
 * @param {Array} arr - input array
 * @param {String} path - key path used when deep getting and setting
 * @param {String} [sep] - key path separator
-* @returns {Array|Null} input array or null
+* @returns {Array} input array
 */
 function erfcinv( x, path, sep ) {
 	var len = x.length,
@@ -33,9 +33,9 @@ function erfcinv( x, path, sep ) {
 		for ( i = 0; i < len; i++ ) {
 			v = dget( x[ i ] );
 			if ( typeof v === 'number' ) {
-				dset( x[i], ERFCINV( v ) );
+				dset( x[ i ], ERFCINV( v ) );
 			} else {
-				dset( x[i], NaN );
+				dset( x[ i ], NaN );
 			}
 		}
 	}
diff --git a/lib/matrix.js b/lib/matrix.js
index 5b337eb..0295734 100644
--- a/lib/matrix.js
+++ b/lib/matrix.js
@@ -11,9 +11,9 @@ var ERFCINV = require( './number.js' );
 * FUNCTION: erfcinv( out, matrix )
 *	Evaluates the inverse complementary error function for each matrix element.
 *
-* @param {Matrix} out - output matirx
+* @param {Matrix} out - output matrix
 * @param {Matrix} arr - input matrix
-* @returns {Matrix} output matrix or null
+* @returns {Matrix} output matrix
 */
 function erfcinv( y, x ) {
 	var len = x.length,
diff --git a/lib/validate.js b/lib/validate.js
index 1d677fb..f10ac88 100644
--- a/lib/validate.js
+++ b/lib/validate.js
@@ -16,7 +16,7 @@ var isObject = require( 'validate.io-object' ),
 *
 * @param {Object} opts - destination for validated options
 * @param {Object} options - function options
-* @param {Boolean} [options.copy=true] - boolean indicating if the function should return a new data structure
+* @param {Boolean} [options.copy] - boolean indicating if the function should return a new data structure
 * @param {Function} [options.accessor] - accessor function for accessing array values
 * @param {String} [options.sep] - deep get/set key path separator
 * @param {String} [options.path] - deep get/set key path
diff --git a/test/test.js b/test/test.js
index 3769a4f..19eac16 100644
--- a/test/test.js
+++ b/test/test.js
@@ -117,7 +117,7 @@ describe( 'compute-erfcinv', function tests() {
 			true,
 			undefined,
 			null,
-			// NaN, // allowed
+			NaN,
 			function(){},
 			{}
 		];