Scores on a English test have average of 85 with standard deviation of 8. What is the probabilty of a student scoring less than 77 on the te

Question

Scores on a English test have average of 85 with standard deviation of 8. What is the probabilty of a student scoring less than 77 on the test? Write your answer as a percent.

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Isabelle 3 days 2021-10-11T23:34:31+00:00 2 Answers 0

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    0
    2021-10-11T23:35:39+00:00

    Answer:47.725%

    If the mean (μ) is 80, and the standard deviation (σ) is 5, then all scores between 80 and 90 would fall between 0 and 2 standard deviations above the mean.

    Using the equation for Z score (Z = (X-μ)/σ) for each X value (80 and 90) then the Z scores are 0 and 2, respectively.  

    Using a normal distribution table, it can be found that P(80 < z) = .5 (this is the probability that a random score would be greater than 80.  It makes sense that it is .5 or 50% because 80 is the mean.)

    And the P(90 > z) = .97725.  (this is the probability that a random score would be less than 90.)

    0
    2021-10-11T23:35:47+00:00

    Answer:

    10

    Step-by-step explanation:

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