/sci/ - Science & Math

How would I go about answering this problem? My book isn't really clear
>Pay attention to both conditions for inference in the following box that summarizes the confidence interval: we must, as usual, be willing to regard the sample as an SRS from the population, and the sample must have both enough successes and enough failures. The condition on successes and failures ensures that the sample size is large enough to use the Normal approximation without knowing p.
How would I even go about defining these different measurements as failures or successes?