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Scores on a visual perception test are normally distributed with a mean of 2020 and a standard deviation of 250.

a)If one subject is randomly selected and tested, find the probability of a score greater than 1800
b)if 50 subjects are randomly selected and tested fid the probability that the sample mean is between 2000 and 2100

  • statistics -

    a) Z = (score-mean)/SD

    b) Z = (score-mean)/SEm

    SEm = SD/√n

    Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions/probabilities related to the Z scores.

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