Statistics

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A normal distribution has a mean of ƒÝ = 100 with ƒã = 20. If one score is randomly selected from this distribution, what is the probability that the score will have a value between X = 90 and X = 110?
a. 0.6915
b. 0.3085
c. 0.1915
d. 0.3830

  • Statistics -

    z = (90-100)/20 = -.5
    z table = 0.3085
    z = (110-100)/20 = .5

    z table = 0.6915

    0.6915-0.3085 = 0.3830
    D

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