or how about this?
100 people have an IQ of 100
50 have an IQ of 90
50 have an IQ of 80
50 have an IQ of 70
50 have an IQ of 60
what is the average IQ of the group?
how many were above average?
how many are below average?
Because extremely low or extremely high scores distort the average. Futhermore, your contrived distribution has an average of 83.3333 and a median between 80 and 90, both of which are below the mean of 100 which is frequently considered the mean. It should be noted ththat your ditribution has 100 at a score of 100 and 200 below 100.