So in a normalized t distribution, you're going to have a mean of 0. And what you're going to do is you want to figure out the probability of getting a t value at least this extreme. So this is your t value you would get, and then you essentially figure out the area under the curve right over there. And so a very easy rule of thumb is calculate this quantity either way. Calculate this quantity either way. If you have more than 30 samples, if your sample size is more than 30, your sample standard deviation is going to be a good approximator for your population standard deviation, and so this whole thing is going to be approximately normally distributed. And so you can use a z table to figure out the probability of getting a result at least that extreme.