Question

A fair coin comes up 'heads' 50% of the time. If we toss such a coin eight times in a row, what is the probability, written as a percentage, that exactly five of those tosses are 'heads'?

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Answer 1

21.875%.

Explanation:

This is a Binomial Probability Distribution.

Prob (exactly 5 heads) = 8C5(0.5)^5(0.5)^3

= 56 * 3.90625 * 10^-3

= 0.21875

= 21.875%.