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  1. MHB Apprentice

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    #1
    Pay attention to the table below.
    $ \displaystyle \begin{array}{|c|c|c|c|c|c|}\hline Frequency & 5 & 6 & 7 & 8 & 9 \\ \hline Score & 6 & 6 & 10 & 15 & 5\\ \hline \end{array}$
    The amount of students who get above average are...
    A. 9 students
    B. 17 students
    C. 18 students
    D. 26 students
    I got the average as $ \displaystyle \frac{291}{35}$, which is eight point something. So, I got 7 + 8 = 15 as the answer, but it was not in the option. I then assume that the frequency and score must be switched, but now I got $ \displaystyle \frac{291}{42}$ which is six point something, so the answer should be 10 + 15 + 5 = 30 which was not in the options either. Where did I go wrong?

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    #2
    Looking at the provided table, it appears the frequency and score are switched. Let's assume they are...

    Using a weighted average, I get a mean score of:

    $ \displaystyle \overline{x}=\frac{6\cdot5+6\cdot6+10\cdot7+15\cdot8+5\cdot9}{6+6+10+15+5}=\frac{301}{42}=\frac{43}{6}=7.1\overline{6}$

    It would appear 20 students scored higher than the mean.

  3. MHB Apprentice

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    #3 Thread Author
    That means, still no answer?

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