The random variable X has the following probability mass function. X -1 0 2 6 7
P(x) 0.3 0.1 0.3 0.2 0.1

Required:
a. Find the probability P( -1 < X ≤ 2) =
b. Find the cumulative distribution function F(x) and calculate F(3.2) =
c. E(X) =
d. Var(X) =
e. Suppose the number of errors in a piece of software has a Poisson distribution with parameter λ=3. The probability that there are 5 errors in a piece of software is .