For X ∼ Bin(n, p), show that E(X) = np and Var(X) = np(1 − p)
Our book defines this as true, but I don't know how to actually prove it.
According to the experian automotive, 35% of all car owning households have three or more cars.
In a random sample 20 car owning households, what is the probability that exactly 6 have three or more cars?