Question

A class had 20 A’s, 8 B’s, 7 C’s, 1 D and 3 F’s. The median score received what letter grade?

Answer 1

The median of a sample is the value m corresponding to the half of total sum of
frequences.
Notice that the scores A,B, C,D, F are not numberical, so the
median depends on their particular ordering.
Assume that they are ordered in
alphabetic order: A, B, C, D, F

So we have the following
table:

Score : A B & C
D F
Frequences: 20& 8 & 7 1 &
3
Cummulative frequences: 20 28 35 & 36 39
The sum of all
frequences is& 20+8+7+3+1=39,
so the half of it 19.5.
This
corresponds to letter A.