EXPLANATION
A simple event is an event with only one outcome. In this case, we are rolling a 4 so this is a compound event with more than one outcome.
So the size of the sample space is 1,2,3,4,5,6 and to get a 4 when rolling a six-sided die is:
Probability= Number of desired outcomes/Number of possible outcomes
Replacing terms:
1/6=0.167
So, the answer is 0.167.