A random variable takes the values 3, 4 and 1 with probabilities 1/2, 1/3 and 1/6 respectively. What is its expected value?
Answer and explanation
Correct answer: A. 3
- Step 1: E[X] = Σ x·p = 3/2 + 4/3 + 1/6. Step 2. = 3. Answer: 3. Why not the others: 2.7 is what you get if you average the values without weights. 8 is what you get if you add the values. 4 is what you get if you miscalculate one term.
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