1)the probability of 2 heads in 4 times ?(adsbygoogle = window.adsbygoogle || []).push({});

2)the probability of less than one head once?

3)the probability of more than 2 tails in 3 times ?

4)the expected number of two tails ?

5)the variance of the number of 2 heads

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# Homework Help: Two coin are tossed 4 times ,find?

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