00:01
In this question, there is a normal distribution.
00:03
So the mean is given here, which is denoted by mu, which is 182 .9, and the population standard division is also given here, which is 20.
00:11
So i can define the random variable x, normally distributed, the mean, and the standard division.
00:17
So we have to find the percentile.
00:20
So the percentile, which is denoted by p, let's say, we don't know the percentile here, let's say some question mark, and this was given as 150.
00:29
So what that means, if i just graph the normal distribution, the mean score is the middle point, which is 182 .9, and the 150, which is over here, in order to get the percentile for the 150, we need to just get the area to the left of 150.
00:45
How we can just get this area? let's say this is x is less than 150.
00:49
I'm going to use the graphing display calculator application normalcdf.
00:53
So when we look at the lower boundary, that goes to negative infinity.
00:56
So i'm going to put a very small number, that means negative 10 to the power 99...