1. A coin is to be tossed until a head appears twice in a row. What is the sample space for this experiment? If the coin is fair, what is the probability that it will be tossed exactly four times?

2. Let E, F, G be three events. Find expressions for the events that of E, F, G

(a) only F occurs,

(b) both E and F but not G occur,

(c) at least one event occurs,

(d) at least two events occur,

(e) all three events occur,

(f) none occurs,

(g) at most one occurs,

(h) at most two occur.