Unit 4: Statistics and Probability
Topic 4.7: Discrete Probability Distributions Questions
Practice 10 exam-style questions for IB Math AI SL Topic 4.7. Review the question stems below, then unlock the full Question Bank to access markschemes, model answers, and AI grading.
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State what E(X) represents in practical terms.
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A discrete random variable has P(X=2) = 0.3, P(X=4) = 0.5, P(X=6) = 0.2. Find P(X ≤ 4).
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A fair six-sided die is rolled. Find E(X), the expected score.
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A discrete random variable X has P(X=1) = 0.2, P(X=2) = 0.5, P(X=3) = k. Find k.
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Find E(X) for the distribution P(X=0) = 0.4, P(X=1) = 0.4, P(X=2) = 0.2.
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A spinner scores X with P(X=1) = 0.5, P(X=3) = 0.3, P(X=10) = 0.2. Find the expected score and explain why the spinner rarely shows the expected value.
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For a distribution with E(X) = 2.4, a game pays out X dollars and costs $2.40 to play. State whether the game is fair.
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A discrete random variable X has the probability distribution shown: P(X=1) = 0.1, P(X=2) = 0.3, P(X=3) = k, P(X=4) = 0.2.
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A discrete random variable X takes values 1, 2 and 3 with P(X=1) = 0.5, P(X=2) = 0.3, P(X=3) = 0.2. The experiment is performed twice independently.
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In a fairground game, a player spins a wheel and wins a prize X dollars. The distribution is P(X=0) = 0.5, P(X=1) = 0.3, P(X=5) = 0.2. It costs $2 to play.
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