Nevertheless, regardless of the tuition fee factor, the plots show clear patterns of drop out probability:

The probability remains at a high level when the average grade is between 0 and 10, then declines rapidly as the average grade moves from 10 to 13, and finally reaches a plateau again beyond that; There are two sharp decline in the second plot, when the average approved curricular unites exceed 5 or 14; The probability remains at a low level when students' age at enrollment is below 20, then increases rapidly as the age moves from 20 to 23, reaching a plateau beyond that.@