 As we mentioned in an earlier video, Excel's data analysis regression tool gives you a set of confidence intervals around the intercept coefficient and the slope coefficient. Here the 95% interval are shown. But if we wanted to find the confidence intervals around these predictions, it's a little more complicated than Excel does not give you a tool, and to do it is a fairly complex set of equations. Not to worry, we've given you in your assignment materials an Excel calculator setup to do the job. We're going to need to copy our data, our x and y values into the calculator. I want to highlight those, let's click and copy. Here's the calculator, it's similar to those you had in one of your earlier assignments. This one is called the CI and PI for confidence interval and prediction interval calculator for regression. And in the same way, the blue cells are where you enter your data, the yellow cells automatically calculate. Here be very careful, notice that column F is labeled x for your predictor variable y for your response variable. Make sure that the data you copy in is in that order. Ours is, I'm going to click there and just click paste. And I've got my x value, my predictor value, and my y values in there now. Over here, I need to put in the value that we would predict. The first one is 55, I'm going to put that in, 95% confidence level. And we get the 19.98899 that we got using the equation on the regression output. This calculator calculates the interval half width or in some cases the margin of error which is 230.34 and that gives us the upper and lower confidence interval limit. In the bottom we've got the prediction interval limits and you notice that the half widths are much larger for predictions than for the confidence interval. And that is because if we're using the confidence interval, we should be trying to predict a value of the mean of a data set for predictions where we want a specific x value and a specific y value. We should use the prediction intervals. There's a lot more uncertainty when you have a specific data value as opposed to a mean data value and that's why the prediction interval is much wider. But I'll leave it to you for your assignment, do a little more research to be able to state that more clearly as to why the prediction interval might be larger. All you need to do for the other sizes is just to change out the width. I want to put 150 in there and it will recalculate and give me those values. What you can do is just to copy this sheet and paste it, just the values. We show you how to do that. We want to select this information, right click, copy. I'm going to insert a new worksheet, select that first cell, right click, bring up the special menu. You want to paste the values first of all and then while it's still selected, right click again and then click the formatting and that will give you everything correct. You might know on this copy there are no underlying formulas so you'll have to go back to the original to change and calculate those. But this is a good way to create a table that you can copy, paste and insert into your report.