00:01
We are looking at a normal distribution.
00:03
I will start by drawing a normal curve.
00:07
Total area under this curve is 1, or 100%, and it is symmetric.
00:11
0 .5 below the mean, 0 .5 above the mean.
00:14
The mean mu is 174, standard deviation sigma is 20.
00:20
I want the probability that x, a random observation from this normal distribution, is greater than 155.
00:29
So that's below the mean, mark it on here.
00:32
Greater than means i want the area to the right, everything above this value.
00:39
So to find this area, you need something with the normal distribution already built in, because the function you would have to integrate to get this area under the curve is far too complicated to do by hand...