There are 2 independent events A and B. The probability that event A occurs is 0.4 and the probability that event B occurs is 0.3. Find the probabilities that
(a) both A and B occur,
(b) either A or B occurs but not both,
(c) neither A nor B occur
M1 probability
2010-08-07 6:27 am
回答 (2)
2010-08-08 7:38 am
✔ 最佳答案
for (b), why i can't do like this:0.3 + 0.4 - 0.3*0.4
因為現在有兩件事, 第一個 0.3 即 B occurs no matter A's state
0.3 x 1 = 0.3 x (0.4+0.6) = 0.3 x 0.4 + 0.3 x 0.6
0.3 x 0.4 已經 violate "but not both"
2010-08-07 6:43 am
(a) both A and B occur,
0.3*0.4 = 0.12
(b) either A or B occurs but not both,
0.3*(1-0.4) + 0.4*(1-0.3) = 0.46
(c) neither A nor B occur
(1-0.4)(1-0.3) = 0.42
0.3*0.4 = 0.12
(b) either A or B occurs but not both,
0.3*(1-0.4) + 0.4*(1-0.3) = 0.46
(c) neither A nor B occur
(1-0.4)(1-0.3) = 0.42
收錄日期: 2021-04-13 17:25:47
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