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Question
Choose the correct alternative:
If X is a discrete random variable and p(x) is the probability of X, then the expected value of this random variable is equal to
Options
`sum"f"(x)`
`sum[x + "f"(x)]`
`sum"f"(x) + x`
`sumx"p"(x)`
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Solution
`sumx"p"(x)`
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