A sample of n= 9 scores has a mean of M= 13. After one score is added, the mean is found to be M=12. What is the value of the score added?

1 Answer

Relevance
  • User
    Lv 7
    1 month ago

    >> A sample of n= 9 scores has a mean of M= 13 <<

    (9 * mean score)/9 = 13

    (obviously, mean score = 13)

    >> After one score is added, the mean is found to be M=12 <<

    ((9 * 13) + x)/10 = 12

    What I've done:

    you count all of the 9 existing scores as if they were the same as the mean score

    and then add the new score

    in the equation for calculating the new mean

    and solve for the new score.

    Just solve that last equation for "x" and you will get the correct answer.

Still have questions? Get your answers by asking now.