If you roll a 6-sided die 6 times, what is the best prediction possible for the number of times you will roll a two?

The best prediction is 1/6 of the times or one time of the six that you will roll a two..

This is because without any interference, each of the six numbers of the dice will have same theoretical probability (which is the probability or chances that is expected.

probability for j is 1/4

while

a is 1/6