Control arm event rate
======================

When assuming the outcomes are Poisson distributed, **multiarm**
requires a value to be specified for the event rate in the control arm,
*λ*<sub>0</sub>, used in the definition of the global null hypothesis,
global alternative hypothesis, and the least favourable configurations,
which are in-turn used to evaluate the operating characteristics
provided by a particular design. Specify your chosen control arm
response rate here. It should be strictly positive.
