### Description

Data arise from 31 male patients who have been treated for superficial bladder cancer, and give the number of recurrent tumours during a particular time after the removal of the primary tumour, along with the size of the original tumour.

### Usage

data("bladdercancer")

### Format

A data frame with 31 observations on the following 3 variables.

time

the duration.

tumorsize

a factor with levels <=3cm and >3cm.

number

number of recurrent tumours.

### Details

The aim is the estimate the effect of size of tumour on the number of recurrent tumours.

### Source

G. U. H. Seeber (1998), Poisson Regression. In: Encyclopedia of Biostatistics (P. Armitage and T. Colton, eds), John Wiley & Sons, Chichester.

### Examples