function quantile( p ) {
		var r;
		var q;
		if ( isnan( p ) || p < 0.0 || p > 1.0 ) {
			return NaN;
		}
		if ( p === 0.0 ) {
			return 0.0;
		}
		if ( p === 1.0 ) {
			return ( n * ( n + 1 ) ) / 2;
		}
		r = 0;
		q = -1;
		while ( r < p ) {
			q += 1;
			r += pui * weights( q, n );
		}
		return q;
	}
Evaluates the quantile function of the Wilcoxon signed rank test statistic.

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

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