Assume that you make random guesses for 5 true-or-false questions

Discussion in 'Calculator Requests' started by math_celebrity, Jan 8, 2017.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    Assume that you make random guesses for 5 true-or-false questions.
    (a) What is the probability that you get all 5 answers correct? (Show work and write the answer in simplest fraction form)
    (b) What is the probability of getting the correct answer in the 5th question, given that the first four answers are all wrong? (Show work and write the answer in simplest fraction form)
    (c) If event A is “Getting the correct answer in the 5th question” and event B is “The first four answers are all wrong”. Are event A and event B independent? Please explain.


    (a) Correct Answer on each one is 1/2 or 0.5. Since all are independent events, we have:
    (1/2)^5 = 1/32

    (b) We have 1/2
    (1/2)^4 * 1/2/((1/2)^4)

    c) Independent since you could have gotten correct or wrong on any of the 4 and the probability does not change
     

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