Probability result
37.5%
Exact fraction: 3/8
Decimal: 0.375
The probability of exactly 2 successes is 37.5%.
For a fair coin, the chance of heads on each flip is 1/2. The binomial model counts how many 4-flip sequences contain exactly 2 heads and 2 tails.
Worked steps
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- Inputs: trials = 4, target successes = 2, p = 0.5, event = exactly.
- Formula: P(X = k) = C(n, k)p^k(1-p)^(n-k).
- Substitute: use C(4, k) with p = 1/2 and 1-p = 1/2.
- Steps: evaluate the binomial term for X = 2 and combine them.
- Result: The probability of exactly 2 successes is 37.5%.
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For a fair coin, the chance of heads on each flip is 1/2. The binomial model counts how many 4-flip sequences contain exactly 2 heads and 2 tails.
Formula
Probability model
P(E) = favorable outcomes / total outcomes
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