JEE Main 2024 Mathematics question
If the mean of the following probability distribution of a random variable X:
| X | 0 | 2 | 4 | 6 | 8 | |---|---|---|---|---|---| | P(X) | a | 2a | a + b | 2b | 3b |
is , then the variance of the distribution is
Answer: (B)
Solution
4a + 6b = 1 (probabilities sum) and the mean 8a + 40b = 46/9 give a = 1/12, b = 1/9.
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