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mehran_kimi
mehran_kimi asked in Science & MathematicsMathematics · 1 decade ago

Tossing a Coin and Binomial Distribution?

What is the probability of getting a second head on the 4th

trial of 5 independent trials of tossing a fair coin?

Please, show the work....like the distribution it uses.

Thanks!

1 Answer

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  • Pope
    Lv 7
    1 decade ago
    Favorite Answer

    If you get the second head on the fourth toss, then you must get exactly one head in the first three tosses, and the fourth toss must fall heads.

    P(1 head in 3 tosses) = C(3,1)(1/2)²(1/2) = 3/8

    P(heads on the fourth toss) = 1/2

    P(second head on fourth toss) = (3/8)(1/2) = 3/16

    The fifth toss has no influence on this outcome.

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