So like always, pause this video and see if you can figure it out on your own. Della has a library of 500 songs right over here, and she's trying to figure out the proportion that are sung by a female artist. She doesn't have the time to go through all 500 songs to figure out the true population proportion, P, so instead she takes a sample of 50 songs, N is equal to 50, and from that she calculates a sample proportion, which we could denote with P hat, and she finds that 20 out of the 50 are sung by a female. 20 out of the 50, which is the same thing, is 0.4, and then she wants to construct a 99% confidence interval. So before we even go about constructing the confidence interval, you wanna check to make sure that we're making some valid assumptions, we're using a valid technique. So before we actually calculate the confidence interval, let's just make sure that our sampling distribution is not distorted in some way, and so that we can, with confidence, make a confidence interval. So the first condition is to make sure that your sample is truly random, and they tell us that it's a simple random sample, so we'll take their word for it.