What is the meaning of the `p`

with the overbar ? I guess here it is not referring to the average of the value of `p`

… or is it?

(Initially, I thought it meant the probability of *not* winning, but then on the next line below you have the equation for the probability of winning for `n`

tickets, while to the left of the equals sign again there is the `p`

with overbar, hence my confusion.)