Conference's attendees may optionally register for an additional workshop; assume that each conference has 220 attendees and that the probability of any given attendee attending the workshop is 15%. Answer following questions. Justify key steps in your reasoning.

a. First, figure out which type of probability distribution applies here.

b. Calculate the expected (or mean) number of workshop attendees out of the 220 at the conference and the variance of number of attendees of such workshops over multiple conferences.