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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 A Answers

Skills

    1. (a) 2.36
    2. (b) No. X takes whole numbers only; E(X) is a long-run mean

  2. 23.5

    1. (a) y = 0: 0.36, y = 1: 0.26, y = 2: 0.2, y = 3: 0.18
    2. (b) 1.2
    1. (a) 0.1
    2. (b) 0.8
    3. (c) 3.3
    1. (a) 0.1
    2. (b) 0.5
    3. (c) 0.725

In context

    1. (a) x = 0, 1, 2: 7/22, 35/66, 5/33
    2. (b) 5/6 = 0.833
    1. (a) 1.35
    2. (b) 270
    1. (a) y = 1: 0.14, y = 2: 0.2, y = 3: 0.28, y = 4: 0.38
    2. (b) 2.9

Stretch

    1. (a) x = 0, 1, 2, 3: 1/6, 1/2, 3/10, 1/30
    2. (b) 6/5 = 1.2
    1. (a) 0.15
    2. (b) 2.95
    3. (c) 0.65

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