# 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.