We are also likely to, if we don't know what the actual population standard deviation is, which we typically don't know, we would also calculate the sample standard deviation. Then the next step is we calculate a p-value, and the p-value, which stands for probability value, is the probability of getting a statistic at least this far away from the mean if we were to assume that the null hypothesis is true. So one way to think about it, it is a conditional probability. It is the probability that our sample mean, our sample mean, when we take a sample of size n equals 100, is greater than or equal to 25, 25 minutes given, given our null hypothesis is true. And in other videos, we have talked about how to do this. If we assume that the sampling distribution of the sample means is roughly normal, we can use the sample mean, we can use our sample size, we can use our sample standard deviation, perhaps we use a t-statistic to figure out roughly what this probability is going to be. And then we decide whether we can reject the null hypothesis.