function quantile( p ) {
		if ( isnan( p ) || p < 0.0 || p > 1.0 ) {
			return NaN;
		}
		if ( p < pInflection ) {
			return a + sqrt( fact1 * p );
		}
		if ( p > pInflection ) {
			return b - sqrt( fact2 * ( 1.0 - p ) );
		}
		// Case: p = pInflection
		return c;
	}
Evaluates the quantile function for a triangular distribution.

@private
@param {Probability} p - input value
@returns {number} evaluated quantile function

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