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 isnan = require( '@stdlib/math-base-assert-is-nan' );
  var isInteger = require( '@stdlib/math-base-assert-is-integer' );
  var pow = require( '@stdlib/math-base-special-pow' );
  
  
  // MAIN //
  
  /**
  * Returns the variance of a discrete uniform distribution.
  *
  * @param {integer} a - minimum support
  * @param {integer} b - maximum support
  * @returns {PositiveNumber} variance
  *
  * @example
  * var v = variance( 0, 1 );
  * // returns ~0.25
  *
  * @example
  * var v = variance( 4, 12 );
  * // returns ~6.667
  *
  * @example
  * var v = variance( -4, 4 );
  * // returns ~6.667
  *
  * @example
  * var v = variance( 1, -0.1 );
  * // returns NaN
  *
  * @example
  * var v = variance( 0.5, 1 );
  * // returns NaN
  *
  * @example
  * var v = variance( 2, NaN );
  * // returns NaN
  *
  * @example
  * var v = variance( NaN, 2 );
  * // returns NaN
  */
  function variance( a, b ) {
  	if (
  		isnan( a ) ||
  		isnan( b ) ||
  		!isInteger( a ) ||
  		!isInteger( b ) ||
  		a > b
  	) {
  		return NaN;
  	}
  	return ( pow( b-a+1, 2.0 ) - 1.0 ) / 12.0;
  }
  
  
  // EXPORTS //
  
  module.exports = variance;
  