
Ultimate access to all questions.
Deep dive into the quiz with AI chat providers.
We prepare a focused prompt with your quiz and certificate details so each AI can offer a more tailored, in-depth explanation.
During a disease outbreak, the probability of surviving after an infection is 60%. Determine the probability that at least 8 out of a group of 9 infected persons will survive.
A
0.7
B
0.07
C
0.007
D
0.06
Explanation:
This is a binomial probability problem where:
We need P(X ≥ 8) = P(X = 8) + P(X = 9)
Using the binomial formula: P(X = x) = C(n,x) * p^x * q^(n-x)
P(X = 8) = C(9,8) * (0.6)^8 * (0.4)^1 = 9 * 0.01679616 * 0.4 = 9 * 0.006718464 = 0.060466176
P(X = 9) = C(9,9) * (0.6)^9 * (0.4)^0 = 1 * 0.010077696 * 1 = 0.010077696
P(X ≥ 8) = 0.060466176 + 0.010077696 = 0.070543872 ≈ 0.0705 or 7%
Therefore, the correct answer is 0.07 (Option B).