Exercises 3.12: 24, 30(a)(b)

And:

1. Let $X$ be the number of heads in four tosses of a fair coin. Find the cumulative distribution function of $X$.
2. Suppose $X$ and $Y$ are independent random variables, both with uniform distributions on the integers $-2, -1, 0, 1, 2$. Find the probability mass function for $T = X + Y$.
3. Suppose $X$ and $Y$ are independent random variables, both with uniform distributions on the integers $1, 2, \ldots, 10$. Find the probability mass functions for $W = \max(X, Y)$ and $U = \min(X, Y)$.