[Si] "Expected value" : Sect 1 "Definition and properties"
: Item
"Definitions"; also Item "A general definition of expected value" (find it
before
"Jensen's inequality").
[BT] Sect 2.4 "Expectation, mean, and variance" (pp. 81-83).
[GS] : Sect 6.1 "Expected value of discrete random variables"
(pp. 229-230).
[BT] Sect 2.4 "Expectation, mean, and variance" : Item "mean and
variance of some common random variables" (p. 88-); also Sect 2.5 "Joint
PMF's of multiple random variable" : Example 2.10, and Sect. 2.8 "Summary
and discussion" (p. 116-).
[GS] : Sect 6.1 "Expected value of discrete random variables"
(p. 233, binomial, Poisson; p. 250, Poisson).