For Example 5.2, we derived the joint PMF of three types of fax transmissions:
(a) In a group of four faxes, what is the PMF of the number of 3-page faxes?
(b) In a group of four faxes, what is the expected number of 3-page faxes?
(c) Given that there are two 3-page faxes in a group of four, what is the joint PMF of the number of 1-page faxes and the number of 2-page faxes?
(d) Given that there are two 3-page faxes in a group of four, what is the expected number of 1-page faxes?
(e) In a group of four faxes, what is the joint PMF of the number of 1-page faxes and the number of 2-page faxes?