When Poisson Is Not Close Enough
You roll 24 fair six-sided dice and want the probability that at least four of them show a 5. A colleague replaces the Binomial count by a Poisson with the same mean:
from math import comb, exp, factorial
n, p = 24, 1 / 6
lam = n * p # 4.0
approx = 1 - sum(exp(-lam) * lam**k / factorial(k) for k in range(4))
print(round(approx, 3)) # 0.567
That 0.567 is not the answer. Report the exact probability that at least four of the 24 dice show a 5.
Answer format: round to 3 decimal places.
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