function quantile( r ) {
		if ( isnan( r ) || r < 0.0 || r > 1.0 ) {
			return NaN;
		}
		if ( r <= 1.0 - p ) {
			return 0;
		}
		return 1;
	}
Evaluates the quantile function for a Bernoulli distribution.

@private
@param {Probability} r - input value
@returns {NonNegativeInteger} evaluated quantile function

@example
var y = quantile( 0.3 );
// returns <number>