function weibull2( k, lambda ) {
		if (
			isnan( k ) ||
			isnan( lambda ) ||
			k <= 0.0 ||
			lambda <= 0.0
		) {
			return NaN;
		}
		return weibull0( rand, k, lambda );
	}
Returns a pseudorandom number drawn from a Weibull distribution.

@private
@param {PositiveNumber} k - scale parameter
@param {PositiveNumber} lambda - shape parameter
@returns {NonNegativeNumber} pseudorandom number

@example
var v = weibull2( 2.0, 1.0 );
// returns <number>

@example
var v = weibull2( 3.0, 0.0 );
// returns NaN

@example
var v = weibull2( 0.0, 2.0 );
// returns NaN

@example
var v = weibull2( NaN, NaN );
// returns NaN