Let X denote the number of Canon SLR cameras sold during a particular week by a certain store. The pmf of X is x 0 1 2 s 4 P x { x ) .1 .2 .3 .25 .15 Sixty percent of all customers who purchase these...

Let X denote the number of Canon SLR cameras sold during a particular week by a certain store. The pmf of
X is

Sixty percent of all customers who purchase these cameras also buy an extended warranty. Let
Y denote the
number of purchasers during this week who buy an extended warranty.

a. What is
P(X
= 4,
Y
=
2)? (Hi This probability equals
P(

Y
= 2/X = 4).P(X
= 4) now think of the four purchases four trials of a binomial experiment, with success on atrial corresponding to buying  an extended warranty.]

 b. Calculate
P(X
= Y).

c. Determine the joint pmf of
X
and Y and then the marginal pmf of Y.