public abstract double ProbabilityDensity(
	double x
)Public MustOverride Function ProbabilityDensity ( 
	x As Double
) As Doublepublic:
virtual double ProbabilityDensity(
	double x
) abstractabstract ProbabilityDensity : 
        x : float -> float The probability density function (PDF) gives the relative probabilities of obtaining different values.