00:01
So the beauty of the normal distribution is that it is symmetric around zero.
00:06
So when we're looking at z values and all the z values just live down here on the number line, not scale because unfortunately i am not an artist.
00:16
But if we think about the things we know about the normal distribution, is that everything's symmetric around zero and the total area underneath the curve has to add up to one or 100%.
00:28
So if we're looking for 99 % in between 2 z scores, this one's a negative z score because it's on the left of zero, this one's a positive z score because it's on the right of zero, and then everything in between the area under the curve is that 0 .99 % which means that this little area out here and this little area out here have to add up to the remaining 1%.
00:57
So this is going to be, half of a percent, and this is going to be the other half of a percent, because when we add up the three values, we do in fact get one or 100 percent.
01:10
Now, depending on your z table, right? so it's got, oops, we're just going to scroll down here...