We are given with the number of games and their frequency. To get the average length of a World Series, we need to take the weighted average of the data.
Multiply the number of games by the frequency. Add the all the values and divided by the total frequency
So,
[4 (14) + 5 (13) + 6 (9) + 7 (14)] / (14 + 13 + 9 + 14) = 5.46
