The basic expected value formula is the probability of an event multiplied by the number of times the event happens: (P(Y) * n).
From the data given in the question, Each random variable (Y) has a probability (P)
The expected value will e the sum of the products of (P) x (Y)
-7 x 0.04 => -0.28
-6 x 0.32=> -1.92
-5 x 0.49 => -2.45
-4 x 0.04 => -0.16
-3 x 0.1 => -0.3
-2 x 0.01 => -0.02
Total = -0.28 -1.92 -2.45 -0.16 - 0.3 -0.02 = -5.13
Expected value = -5.13
