1. Discrete distribution question

Hi, I'm stuck with the last two questions on this problem and can't seem tofind any examples in my notes or worksheets - Your help would be greatly appreciated...

A compnay takes on an average of 0.1 new employees per week. Assume that the actual number of employees taken on in a given week is Poissonly distributed.

(i) Find the prob. that more than one employee is taken on in a given week.
THIS IS OK AND I GET 0.00468

(ii) Let Y denote the number of weeks pass without a new employee being taken on. calculate the expectation of Y.
I THINK THIS IS A GEOMETRIC DISTRIBUTION BUT NOT SURE WHERE OR WHAT TO DO

(iii) Calculate the prob. that over the course of 50 weeks there is just one week when more than one new employee is taken on.

??

2. Originally Posted by dojo
(ii) Let Y denote the number of weeks pass without a new employee being taken on. calculate the expectation of Y.
I THINK THIS IS A GEOMETRIC DISTRIBUTION BUT NOT SURE WHERE OR WHAT TO DO
It is not geometric. Do a calculation, and use the fact that $P(N=0)=e^{-\lambda}$.

(iii) Calculate the prob. that over the course of 50 weeks there is just one week when more than one new employee is taken on.

??
What is the probability in a week that more than one employee is taken on? What is probability that no employees are taken on?