Choosing a distribution and approximations

Choosing a distribution and approximations Quiz

Spec 4.3 · Edexcel A-Level Maths: Quiz

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5 questions, one answer each

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  1. 1. X∼B(100,0.5)X\sim B(100,0.5) is approximated by a Normal distribution. Which is correct?

    • A. N(50,5)N(50,5)
    • B. N(50,50)N(50,50)
    • C. N(50,25)N(50,25)
    • D. N(100,25)N(100,25)

  2. 2. X∼B(40,0.5)X\sim B(40,0.5) and YY is its Normal approximation. P(X≥25)≈P(Y>?)P(X\ge25)\approx P(Y>?)

    • A. 24.524.5
    • B. 25.525.5
    • C. 2525
    • D. 2424

  3. 3. Which situation is least suitable for a binomial model?

    • A. Sixes in 20 rolls of a fair die
    • B. Heads in 50 tosses of a fair coin
    • C. Faulty bulbs in a random sample of 10 from a very large batch
    • D. Red cards in 6 cards dealt without replacement from a pack of 10 cards

  4. 4. Why is a continuity correction used?

    • A. To make the variance equal to npnp
    • B. Because a discrete variable is approximated by a continuous one
    • C. To make pp closer to 0.5
    • D. To change the mean of the Normal distribution

  5. 5. X∼B(30,0.5)X\sim B(30,0.5) and YY is its Normal approximation. P(X<14)≈P(Y<?)P(X<14)\approx P(Y<?)

    • A. 14.514.5
    • B. 1414
    • C. 13.513.5
    • D. 1313

Quiz