Exam 1

  1. Metainformation

    Tag Value
    fileProbability_uva-addition-rule-540-en_uva-addition-rule-540-en
    nameuva-addition-rule-540-en
    sectionProbability/Elementary Probability/General Rules/Addition rule
    typeschoice
    solutionFALSE, FALSE, TRUE, FALSE
    TypeConceptual
    LanguageEnglish
    LevelStatistical Literacy
    IRT-Difficulty2
    p-value0.5905

    Question

    The following cross tabulation includes data from 200 individuals for two variables A and B.

    ——- ——- ——- ——- A = 1 A = 2 A = 3 B = 1 50 36 64 B = 2 20 12 18 ——- ——- ——- ——-

    The events A=2 and B=1 are


    1. FALSE: Dependent, because P(A=2 ∪ B=1) ≠ P(A=2) + P(B=1)
    2. FALSE: Dependent, because P(A=2 | B=1) P(B=1 | A=2)
    3. TRUE: Independent, because P(A=2 ∩ B=1) = P(A=2) P(B=1)
    4. FALSE: Independent, because P(A=2 ∪ B=1) = P(A=2) + P(B=1) - P(A=2 ∩ B=1)

    1. Dependent, because P(A=2 ∪ B=1) ≠ P(A=2) + P(B=1): Incorrect
    2. Dependent, because P(A=2 | B=1) P(B=1 | A=2): Incorrect
    3. Independent, because P(A=2 ∩ B=1) = P(A=2) P(B=1): Correct
    4. Independent, because P(A=2 ∪ B=1) = P(A=2) + P(B=1) - P(A=2 ∩ B=1): Incorrect