function validate( opts, options ) {
	if ( !isObject( options ) ) {
		return new TypeError( format( 'invalid argument. Options argument must be an object. Value: `%s`.', options ) );
	}
	if ( hasOwnProp( options, 'alpha' ) ) {
		opts.alpha = options.alpha;
		if (
			!isNumber( opts.alpha ) ||
			isnan( opts.alpha ) ||
			opts.alpha < 0.0 ||
			opts.alpha > 1.0
		) {
			return new TypeError( format( 'invalid option. `%s` option must be a number on the interval: [0, 1]. Option: `%s`.', 'alpha', opts.alpha ) );
		}
	}
	if ( hasOwnProp( options, 'alternative' ) ) {
		opts.alternative = options.alternative;
		if ( indexOf( alternative, opts.alternative ) === -1 ) {
			return new TypeError( format( 'invalid option. `%s` option must be one of the following: "%s". Option: `%s`.', 'alternative', alternative.join( '", "' ), opts.alternative ) );
		}
	}
	if ( hasOwnProp( options, 'rho' ) ) {
		opts.rho = options.rho;
		if (
			!isNumber( opts.rho ) ||
			isnan( opts.rho ) ||
			opts.rho < -1.0 ||
			opts.rho > 1.0
		) {
			return new TypeError( format( 'invalid option. `%s` option must be a number on the interval: [-1, 1]. Option: `%s`.', 'rho', opts.rho ) );
		}
	}
	return null;
}
Validates function options.

@private
@param {Object} opts - destination for validated options
@param {Options} options - function options
@param {number} [options.alpha] - significance level
@param {string} [options.alternative] - alternative hypothesis (`two-sided`, `less` or `greater`)
@param {number} [options.rho] - correlation coefficient under HO
@returns {(null|Error)} null or an error

@example
var opts = {};
var options = {
    'alpha': 0.01,
    'rho': 0.8
};
var err = validate( opts, options );
if ( err ) {
    throw err;
}