Qualities are rates and the arithmetic mean gives an incorrect result for average training time. The harmonic mean (
en.wikipedia.org /wiki/Ha... ) is the correct method for finding the average rate of improvement. The EQ I calculated earlier is simply the weighted harmonic mean multiplied by the drop from CL as Ciukitu stated above.
Qualities can be thought of as a percent of the maximum possible training rate. So a player with 100 quality will train at 100% of the maximum possible that his facilities and staff would allow. Similarly 50 quality and 1 quality are 50% and 1% respectively. If, for example, the maximum possible training per day would be 1 point, then the attribute with 100 quality would take 1 day to gain 1 point, the attribute with 50 quality would take 2 days, and the attribute with 1 quality would take 100 days.
So, if we have 2 players training 2 attributes that they want to keep in a 1:1 ratio, one player with qualities 99 and 1, and the other with 50 in both, the average calculated in the usual way is 50 for both and would seem to indicate that overall they will advance at the same rate. This is false however because the player with 99 and 1 qualities will advance much slower then the player with 50 in both. The harmonic means are 1.98 and 50 and give a true indication of just how long it will take the 99 and 1 player to gain 2 points overall.