If X follows a binomial distribution with n = 10 and p = 0.4, what is Var(X)?
Correct answer: C. 2.4
- A. 1.6
- B. 2.0
- C. 2.4
- D. 4.0
Explanation
For a binomial variable, variance equals np(1 − p). Thus, Var(X) = 10(0.4)(0.6) = 2.4, not np, which is the expected value.
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Probability covers sample spaces, events, complements, mutually exclusive and independent events, conditional probability, addition and multiplication rules, and tree diagrams. Distributions describe discrete random variables through probability tables, expected value and variance, including binomial and normal models where their conditions and parameters must be identified.
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