14.3 Axiomatic Approach to Probability

Let a sample space be $S = \{\omega_1, \omega_2, \omega_3, \omega_4, \omega_5, \omega_6\}$. Which of the following assignments of probabilities are valid? (a) $P(\omega_i) = 1/6$ for all i (b) $P(\omega_i) = 1/5$ for i=1..5, $P(\omega_6) = 0$ (c) $P(\omega_1) = 2/3, P(\omega_2) = 1/3$, others negative.