A random variable takes the values 4, 2 and 3 with probabilities 1/2, 1/3 and 1/6 respectively. What is its expected value?
Answer and explanation
Correct answer: C. 3.2
- Step 1: E[X] = Σ x·p = 4/2 + 2/3 + 3/6. Step 2. = 3.2. Answer: 3.2. Why not the others: 3 is what you get if you average the values without weights. 9 is what you get if you add the values. 4.2 is what you get if you miscalculate one term.
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