Chapter 12.2, Problem 13E

For the experiments in Exercises $9-14,$write out the sample space $S$, choosing an $S$with equally likely outcomes, if possible. Then give the value of $n(S)$and tell whether the outcomes in $S$are equally likely. Finally, write the indicated events in set notation.

A coin is flipped until two heads appear, up to a maximum of four flips. (If three tails are flipped, the coin is still tossed a fourth time to complete the experiment.)

a. The coin is tossed four times.

b. Exactly two heads are tossed.

c. No heads are tossed.