The dot plot of flip times increased gradually between 1, 2 and 3. The dot plot grew sharply from 3 to 4 and then 6.
Step-by-step explanation:
There are only 5 probabilities. It took Martin 1,2,3,4 and 6 flips to land a tail up. That 1,2,3 times of flips to land a tail up happened once. 4 times of flips to land a tail up happened 8 times. The greatest number of flips took to land tails up was 6 but the question didn't give details how many times it happens.