Let X be the number of smoke alarms in an apartment. From government data, you find the

Question:

Let X be the number of smoke alarms in an apartment. From government data, you find the mass of X is
px(0) = 0.05
px(l) = 0.15
px(2) = 0.35
px(3) = 0.30
Px(A) = 0.10
Px(5) = 0.05
Assume each alarm requires one battery per year, and batteries cost $2.35.
a. What is the expected cost in batteries for smoke alarms for a randomly selected apartment?
b. What is the variance of the cost?