Idist {EpiLPS} | R Documentation |

## Density function and discrete distribution for a disease interval

### Description

This function computes the probability density function and probability mass function for a disease interval (e.g. the serial interval defined as the time elapsed between the symptom onset in an infector and the onset of symptoms in the secondary cases generated by that infector). It takes as input the mean and the standard deviation of the disease interval (expressed in days) and gives as an output the interval distribution based on a chosen parametric family.

### Usage

```
Idist(mean, sd, dist = c("gamma", "weibull", "lognorm"), probs = NULL)
```

### Arguments

`mean` |
The mean of the disease interval (must be larger than 1). |

`sd` |
A positive and finite real number corresponding to the standard deviation of the disease interval. |

`dist` |
A choice among a Gamma, Weibull or Log-normal distribution for the disease interval. |

`probs` |
A vector of probabilities for the interval distribution. |

### Details

The discretization is based on the formula in Held et al. (2019).

### Value

A list of class `Idist`

containing a vector of probabilities
corresponding to the discrete distribution of the disease interval,
the name of the chosen parametric distribution and its parameters.

### Author(s)

Oswaldo Gressani oswaldo_gressani@hotmail.fr

### References

Held, L., Hens, N., D O'Neill, P., and Wallinga, J. (2019).
Handbook of infectious disease data analysis. *CRC Press*.

### Examples

```
Idist(mean = 2.6, sd = 1.5)
```

*EpiLPS*version 1.3.0 Index]