Variance of fair die roll (1-6):
A3.5
B6
C1
D35/12 ≈ 2.92 (= ((6²-1)/12) for uniform discrete)
Answer & Solution
Correct answer: D. 35/12 ≈ 2.92 (= ((6²-1)/12) for uniform discrete)
For uniform discrete {1,2,...,n}: Var = (n²-1)/12. For n=6: 35/12. Mean = (n+1)/2 = 3.5. SD = sqrt(35/12) ≈ 1.71.
Related questions
For a random variable X, the variance Var(X) equalsIf P(A) = 0.4, P(B|A) = 0.5, then P(A ∩ B) equalsTwo dice are rolled. Let E = "sum is 8" and F = "at least one die shows 4". Then P(E|F) eqE and F are independent events with P(E) = 0.3 and P(F) = 0.5. Then P(E ∪ F) equalsA card is drawn at random from a well-shuffled deck of 52. E = "card is a face card" (KingFor a Binomial distribution B(n, p), the probability of exactly r successes isThe variance of the number of heads in 3 fair-coin tosses isA random variable X counts the number of heads in 3 tosses of a fair coin. The mean E(X) i