pdfPoisson

Purpose

Computes the Poisson probability mass function.

Format

p = pdfPoisson(x, lambda)
Parameters:
  • x (NxK matrix, Nx1 vector or scalar) – x must be a positive whole number.
  • lambda (NxK matrix, Nx1 vector or scalar) – The mean parameter. ExE conformable with x.
Returns:

p (NxK matrix, Nx1 vector or scalar) – the Poisson probability mass function evaluated at the elements in x.

Examples

Basic example

p = pdfPoisson(190, 200);

After the code above, p is equal to:

0.02243

Vector input

events = { 170,
           180,
           190,
           200 };
p = pdfPoisson(events, 200);

After the code above, p is equal to:

0.00285
0.01056
0.02243
0.02820

Vector Inputs

events = { 170,
           180,
           190,
           200 };
lambda = { 180,
           190,
           200,
           210 };

p = pdfPoisson(events, lambda);

After the code above, p is equal to:

0.02304
0.02274
0.02243
0.02214

Remarks

For invalid inputs, pdfPoisson() will return a scalar error code which, when its value is assessed by function scalerr(), corresponds to the invalid input. If the first input is out of range, scalerr() will return a 1; if the second is out of range, scalerr() will return a 2; etc.