A cereal company is putting 1 of 4 prizes in each box of cereal. The prizes are evenly distributed so the probability of winning any given prize is always 1/4.

Lily wonders how many boxes she should expect to buy to get all 4 prizes. She carried out 20 trials of a

simulation and her results are shown below. Each dot represents how many boxes it took to get all 4 prizes in

that trial.

4

5

6

7

8

9

10 11 12 13 14 15

# of boxes purchased

Use her results to estimate the probability that it takes fewer than 7 boxes to get all 4 prizes.

Give your answer as either a fraction or a decimal.

P(fewer than 7 boxes) -