CFA CFA Level 1 Question of the Week – Quantitative Methods

Question of the Week – Quantitative Methods

  • Author
    Posts
    • Avatar of AdaptPrepAdaptPrep
      Participant
        • Undecided
        Up
        0
        ::

        A portfolio manager has a tight tracking error
        of 50 basis points. The manager expects to be within this tracking error for a
        given quarter 85% of the time. If that expectation is correct and each quarter
        is independent, the probability that the manager is within the tracking error
        for at least 7 of the next 8 quarters is closest to:

        • 35%
        • 65%
        • 75%
      • Avatar of AdaptPrepAdaptPrep
        Participant
          • Undecided
          Up
          2
          ::

          We will use a binomial distribution with p = 0.85 and n = 10. We want to calculate:

          Pr(X >= 7)
          = Pr(X = 7) + Pr(X = 8)

          Pr(X = 7) = (8
          choose 7) * (0.85)^7 * (1 – 0.85)^(8 – 7) = 0.3847

          Pr(X = 8) = (8
          choose 8) * (0.85)^8 * (1 – 0.85)^(8 – 8) = 0.2725

          Pr(X >= 7)
          = 0.3847 + 0.2725 = 0.6572

        • Avatar of aaronpcjbaaronpcjb
          Participant
            • CFA Level 1
            Up
            2
            ::

            > @AdaptPrep said:
            > We will use a binomial distribution with p = 0.85 and n = 10. We want to calculate:

            You said you set n = 10, did you not mean n = 8?

          • Avatar of AdaptPrepAdaptPrep
            Participant
              • Undecided
              Up
              2
              ::

              Yes, we meant n = 8, not 10. Good catch!

          Viewing 3 reply threads
          • You must be logged in to reply to this topic.