00:01
In this question we are looking at a normal distribution, so i will start by drawing that.
00:10
The total area under this curve is 1, or 100%.
00:13
It's a probability curve.
00:15
And it's symmetric.
00:16
Half of the values are below the mean, half are above the mean.
00:21
The mean here, mu, is 96 .1, standard deviation sigma, 16 .2.
00:27
We are looking for p53, the 53rd percentile, and that separates the bottom 53 % from the top 47%.
00:37
So immediately i know this is going to be on the right side of the curve, just above the mean.
00:42
Because of the symmetry here, the mean is also the median, the 50th percentile.
00:47
I'm looking for the 53rd percentile.
00:50
53 % of the area is to its left.
00:54
So all of this is 0 .53.
00:59
Now, how do i go about finding this? so there are two ways you might go about this.
01:05
First of all, you could use a z -score table.
01:08
You need one that has z -scores to three decimal places.
01:11
Most of them only have two, so i would personally not want to use this.
01:15
The second way is to use technology.
01:19
Now, i'm going to use a ti -84 with the function invnorm...