urgent plzzz

2007-05-08 9:41 am
In 10 tosses of a fair coin, compute the probability of getting 5, 6, 7 or 8 heads.

回答 (2)

2007-05-08 10:20 pm
✔ 最佳答案
Possibility of getting 5 heads
=1/2 ^ 10 * 10C5
= 1/1,024 * 252
= 63/256 (0.2461)

Possibility of getting 6 heads
=1/2 ^ 10 * 10C6
= 1/1,024 * 210
= 105/512 (0.2051)

Possibility of getting 7 heads
=1/2 ^ 10 * 10C7
= 1/1,024 * 120
= 15/128 (0.1172)

Possibility of getting 8 heads
=1/2 ^ 10 * 10C8
= 1/1,024 * 45
= 45/1,024 (0.04395)

*10C5 means = 10! / [(10-5)! * 5!], the number of possibilities of 5 heads in 10 tosses of a fair coin
2007-05-12 8:19 pm
5/10
6/10
7/10
8/10


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