text: /**
  * @license Apache-2.0
  *
  * Copyright (c) 2018 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 isNumber = require( '@stdlib/assert/is-number' ).isPrimitive;
  var isPositive = require( '@stdlib/assert/is-positive-number' ).isPrimitive;
  var isnan = require( '@stdlib/assert/is-nan' );
  
  
  // MAIN //
  
  /**
  * Validates parameters.
  *
  * @private
  * @param {number} mu - location parameter
  * @param {PositiveNumber} sigma - scale paramter
  * @returns {(Error|null)} error or null
  *
  * @example
  * var err = validate( 1.0, 2.0 );
  * if ( err ) {
  *     throw err;
  * }
  */
  function validate( mu, sigma ) {
  	if ( !isNumber( mu ) || isnan( mu ) ) {
  		return new TypeError( 'invalid argument. `mu` must be a number primitive and not `NaN`. Value: `' + mu + '`.' );
  	}
  	if ( !isPositive( sigma ) ) {
  		return new TypeError( 'invalid argument. `sigma` must be a positive number. Value: `' + sigma + '`.' );
  	}
  	return null;
  }
  
  
  // EXPORTS //
  
  module.exports = validate;
  