Probability result
81.25%
Exact fraction: 13/16
Decimal: 0.8125
The probability of at least 2 successes is 81.25%.
For a fair coin, the chance of heads on each flip is 1/2. At least 2 heads means adding the probabilities for 2, 3, 4, and 5 heads across the 5 flips.
Worked steps
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- Inputs: trials = 5, target successes = 2, p = 0.5, event = at least.
- Formula: P(X in range) = sum of C(n, k)p^k(1-p)^(n-k) terms.
- Substitute: use C(5, k) with p = 1/2 and 1-p = 1/2.
- Steps: evaluate the binomial terms for X >= 2 and combine them.
- Result: The probability of at least 2 successes is 81.25%.
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For a fair coin, the chance of heads on each flip is 1/2. At least 2 heads means adding the probabilities for 2, 3, 4, and 5 heads across the 5 flips.
Formula
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P(E) = favorable outcomes / total outcomes
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