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The n candidates for a job have been ranked 1, 2, 3,…, n. Let X = the rank of a randomly selected candidate, so that X has pmf
(this is called the discrete uniform distribution). Compute E(X) and V(X) using the shortcut formula. [Hint: The sum of the first n positive integers is n(n + 1)/2, whereas the sum of their squares is n(n + 1 )(2n + 1 )/6.]
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Chapter 3 Solutions
Probability and Statistics for Engineering and the Sciences