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    Normal Probability

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    Please explain solutions for #21, 22.

    A final Math exam has a normal distribution with mean 73 and standard deviation 3.5.

    21- If one student is randomly selected, find the probability that his score be less than 71:

    A) 0.7158 B) 0.2843 C) 0.4934 D) 0.6432

    22- If 25 students are randomly selected, find the probability that the mean of their scores be less than 71:

    A) 0.9930 B) 0.9979 C) 0.0021 D) 0.0021

    23- Why can the Central Limit be applied in question #22, if the sample size doesn't exceed 30?

    A) Because the theorem is easy to apply
    B) Because the population has a Normal distribution
    C) Because this theorem is very important in inferential statistics.
    D) Because this theorem apply only in scores distributions.

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    https://brainmass.com/statistics/probability/probability-distributions-math-exam-scores-414559

    Solution Preview

    Please see the attachment.

    Probability Math Exam
    A final Math exam has a normal distribution with mean 73 and standard deviation 3.5.

    21- If one student is randomly selected, find the probability that his score be less than 71:

    A) 0.7158 B) 0.2843 C) 0.4934 D) ...

    Solution Summary

    The solution provides step by step method for the calculation of probability using the Z score. Formula for the calculation and Interpretations of the results are also included.

    $2.19

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