MAT 1272 Statistics, SP2014

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  • #13732

    Ezra Halleck
    Participant

    The scores of an exam were normally distributed with a mean of 42 and a standard deviation of 26. The following chart shows cutoffs for student scores (e.g., a student who scores better than a 10 but less than 30 will receive a D):
    scores 10 30 40 50 60 70 80 90
    grade D C C+ B- B B+ A- A
    a. What is the chance that a random student got a B or higher?
    b. What is the chance that a random student failed the exam?
    Note: you must draw separate pictures for each part to get credit!

    #17827

    YinYin A. Li
    Participant

    #17828

    YinYin A. Li
    Participant

    Sorry, I make a mistake, I read the wrong number (x). It should be B=60. So, it should be :
    Z=(60-42)/16=0.6923
    P(Z)=0.7549, (USING THE CHART TO FIND THE PROBABILITY)
    The final answer is A=1-0.7549=0.2451

    #17851

    Ezra Halleck
    Participant

    Good effort. Just remember that this topic will not be on Exam 2.

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