 Hello, today we're going to talk about confidence intervals, finding critical values for a confidence level of 83.6%, find the critical value, round to two decimal places. So that means I want to find the data value or Z score whose area to the right is alpha over two. So first let's find alpha. Alpha is always one minus the confidence level, which would be one minus 0.836, which gives us 0.164. Now alpha over two is this result we just found 0.164 divided by two. This gives us 0.082. This means that in my bell curve, I want to know the data value or the Z score whose area to the right is 0.082. So the region to the right of this here data value I'm trying to find is 0.082. Well, to use Google Sheets to find my data value, I need to know the area to the left. The area to the left of my data value is one minus the area to the right, one minus 0.082. This gives me 0.918. Since we are dealing with Z scores, I know that the mean of my distribution is zero. Standard deviations one. And then as we just calculated, area to the left is 0.918. This is the information we'll put in Google Sheets. So in Google Sheets, you want to make sure you go to the compute tab. The mean is zero. Standard deviations one. And then all you need to do is type in the left tailed area, which is 0.918. Push enter. It turns out that 1.39 is my critical value here. 1.39 is my critical value. So my Z sub alpha over two is 1.39. Thanks for watching.