Find two numbers with a sum of 20 and a difference of 14. options:   3 and 17   –3 and –17   4 and 18   2 and 16

Calculate the mean value (expected value) of the following discrete variable x (10 points): x = 0, 1, 2, 3, 4, 5, 6 p(x) = 0.2, 0.2, 0.15, 0.15, 0.15, 0.1, 0.05