a fair dice is rolled 6times in a experiment
a)what is the probability that "4" is observed twice??
b)what is the probability that the dice comes up an even number exactly 5 times??
PLZPLZ
STATISTICS唔該高手
2011-03-06 8:55 pm
回答 (1)
2011-03-06 9:20 pm
✔ 最佳答案
a)2次在6次中可能分佈數 * 4次非4機率 * 2次是4機率= (6C2) (5/6)^4 (1/6)^2= 3125/15552b)P(even) = 3/6 = 1/2 ,5次在6次中可能分佈數 * 1次非even機率 * 5次是even機率(6C5) (1/2) (1/2)^5= 6/2^6= 3/32
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https://hk.answers.yahoo.com/question/index?qid=20110306000051KK00515