In a statistics mid-term exam graded out of 100 points, the distribution of the exam scores was bi-modal with a mean of 70 points with a sta

Question

In a statistics mid-term exam graded out of 100 points, the distribution of the exam scores was bi-modal with a mean of 70 points with a standard deviation of 10 points. What percentage of students scored between 40 points and 100 points?

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Jasmine 2 weeks 2021-09-12T07:51:41+00:00 2 Answers 0

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    0
    2021-09-12T07:52:55+00:00

    Answer:

    Step-by-step explanation:

    Assuming a normal distribution for the distribution of the points scored by students in the exam, the formula for normal distribution is expressed as

    z = (x – u)/s

    Where

    x = points scored by students

    u = mean score

    s = standard deviation

    From the information given,

    u = 70 points

    s = 10.

    We want to find the probability of students scored between 40 points and 100 points. It is expressed as

    P(40 lesser than x lesser than or equal to 100)

    For x = 40,

    z = (40 – 70)/10 =-3.0

    Looking at the normal distribution table, the corresponding z score is 0.0135

    For x = 100,

    z = (100 – 70)/10 =3.0

    Looking at the normal distribution table, the corresponding z score is 0.99865

    P(40 lesser than x lesser than or equal to 100) = 0.99865 – 0.0135 = 0.98515

    The percentage of students scored between 40 points and 100 points will be 0.986 × 100 = 98.4%

    0
    2021-09-12T07:53:04+00:00

    Step-by-step explanation:

    At least 89%

    ………………………..

    ur welcome

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