But with all of that out of the way, let's actually answer the question. Well, to construct a confidence interval around a statistic, you would take the value of the statistic that you calculated from your sample, so 0.164, and then it would be plus or minus a critical t value, and then this would be driven by the fact that you care about a 95% confidence interval and by the degrees of freedom, and I'll talk about that in a second, and then you would multiply that times the standard error of the statistic, and in this case, the statistic that we care about is the slope, and so this is 0.057 times 0.057, and the reason why we're using a critical t value instead of a critical z value is because our standard error of the statistic is an estimate. We don't actually know the standard deviation of the sampling distribution. So the last thing we have to do is figure out what is this critical t value? You can figure it out using either a calculator or using a table. I'll do it using a table, and to do that, we need to know what the degrees of freedom. Well, when you're doing this with a regression slope like we're doing right now, your degrees of freedom are going to be the number of data points you have minus two so our degrees of freedom are going to be 20 minus two which is equal to 18.