The meteorological department recorded the weather of a town for 30 consecutive days and found that it rained on 18 of those days.
a. (i) Calculate the empirical probability that it rained on a randomly chosen day from these 30 days.
b. (ii) For the next day, classify the event R: “it will rain tomorrow” as certain, impossible, or possible but not certain, giving a clear reason based on the probability found in part (i).
c. (iii) Similarly, classify the complementary event R′: “it will not rain tomorrow”, justifying your answer.