贏錢的機率

【94 東華企研所】統計學
Probability
Suppose that you hold 20 out of a total of 500 tickets sold for a lottery. The grand-prize winner is determined by the random selection of one the 500 tickets. Let G be the event that you win the grand prize. What is the probability that you win the grand prize?
(A) 0.01   (B) 0.02   (C) 0.03  (D) 0.04  (E) 0.05

sol:
  P(G)=20*(1/500)=0.04 --------(D)

每張彩卷贏錢的機率是(1/500)
手上握有20張彩卷
          20*(1/500) =0.04
因此，贏錢的機率是4%。

考統計，也考英文.........