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Given that the general population is normally distributed on a standard scale measuring math aptitude with Mean = 50 (s.d. = 10), approximately what percentage of the population has a math aptitude score between 40 and 60?

  • statistics -

    You need to find the z-score

    (40 - 50)/10 = z

    (60 - 50)/10 = z

    So, you are looking for -1 and +1 standard deviations.

    Find the area between -1 and +1 standard deviation by using a z-table or else by using the 65.. etc, rule.

  • statistics -

    68.2%

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