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IB Mathematics: Applications and Interpretation HL · 13.2: Probability Distributions · 13.2.2

Expected value of a discrete random variable Problem set B Answers

Skills

    1. (a) 1.53
    2. (b) No. X takes whole numbers only; E(X) is a long-run mean

  2. 12.75

    1. (a) y = 0: 0.48, y = 1: 0.3, y = 2: 0.16, y = 3: 0.06
    2. (b) 0.8
    1. (a) 0.3
    2. (b) 0.4
    3. (c) 8.38
    1. (a) 0.1
    2. (b) 0.4
    3. (c) 0.743

In context

    1. (a) x = 0, 1, 2: 5/12, 1/2, 1/12
    2. (b) 2/3 = 0.667
    1. (a) 1.3
    2. (b) 195
    1. (a) y = 2: 0.17, y = 3: 0.21, y = 4: 0.27, y = 5: 0.35
    2. (b) 3.8

Stretch

    1. (a) x = 0, 1, 2, 3: 5/21, 15/28, 3/14, 1/84
    2. (b) 1
    1. (a) 0.2
    2. (b) 2.9
    3. (c) 0.7

jmaths.xyz · AI HL · 13.2.2 Expected value of a discrete random variable