(AKS 24): A set of art exam scores are normally distributed with a mean of 81 points and a standard deviation of 10 points. Calvin got

Question

(AKS 24): A set of art exam scores are normally distributed with a mean of 81 points
and a standard deviation of 10 points. Calvin got a score of 78 on the exam.
What percentage of exam scores are lower than Calvin’s score?

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Jasmine 1 week 2021-10-05T23:28:49+00:00 1 Answer 0

Answers ( )

    0
    2021-10-05T23:30:45+00:00

    Answer:

    Step-by-step explanation:

    Let x be the random variable representing the set of art exam scores. Since they are normally distributed and the population mean and population standard deviation are known, we would apply the formula,

    z = (x – µ)/σ

    Where

    x = sample mean

    µ = population mean

    σ = standard deviation

    From the information given,

    µ = 81

    σ = 10

    the probability of getting a score lower than 78 is expressed as

    P(x < 78)

    For x = 78,

    z = (78 – 81)/10 = – 0.3

    Looking at the normal distribution table, the probability corresponding to the z score is 0.38

    Therefore, the percentage of exam scores that are lower than Calvin’s score is

    0.38 × 100 = 38%

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45:7+7-4:2-5:5*4+35:2 =? ( )