The total number of times the cube was rolled is given by 13 + 16 + 15 + 17 + 19 + 20 = 100
The probability of rolling each number is given by:
P(1) = 13/100 = 13%
P(2) = 16/100 = 16%
P(3) = 15/100 = 15%
P(4) = 17/100 = 17%
P(5) = 19/100 = 19%
P(6) = 20/100 = 20%
Then the probability of rolling a number less or equal to 4 is given by:
P(<=4) = P(1) + P(2) + P(3) + P(4) = 13% + 16% + 15% + 17% = 61%