random.negativeBinomial

random.negativeBinomial, function

def pure random.negativeBinomial(mu: number, d: number): number
def pure random.negativeBinomial(mu: number, d: number, zeroInflation: number): number

Draws a deviate from a negative binomial distribution with mean mu and dispersion d. The third-argument overload adds a zero-inflation mixture.

• mu: the mean of the distribution (non-negative).
• d: the dispersion (must be at least 1).
• zeroInflation: the probability mass at zero, between 0 and 1.

Examples

montecarlo 10000 with
  x = random.negativeBinomial(4, 1.5)
  sample avgX = avg(x)

show scalar "Average sample" with avgX

This outputs the following scalar:

montecarlo 10000 with
  y = random.negativeBinomial(4, 1.5, 0.2)
  sample avgY = avg(y)

show scalar "Average sample (zero-inflated)" with avgY

This outputs the following scalar:

Remarks

When d equals 1, this function behaves like random.poisson(mu).