Let p be the probability of success.
p = P(occurrence of 4 in a ball)
= number of times 4 occurred in all the legal deliveries during powerplay of an inning / total number of balls
= 9091 / (1598*36) = 9091 / 57528 = 0.158
Using the Binomial distribution: n = 36, x : {0, 1, …., 36}, p = 0.158
The whole analysis is given on the Sheets and docx file.