00:01
We're looking at the standard normal curve.
00:02
So i'll start by drawing it.
00:06
The total area under this curve is 1, or 100%, and it's symmetric.
00:10
0 .5 below the mean, 0 .5 above the mean.
00:14
The mean mu is 0, standard deviation is 1.
00:17
You're expected to know the parameters of the standard normal curve.
00:22
In part one, we want the area to the left of minus 1 .45.
00:27
So that's down here, to the left, this bit here.
00:33
So how do we find this shaded area? well, you need something with the normal distribution built in.
00:39
The function you'd have to integrate to get this area is too complicated for us to do this by hand.
00:44
So you could use a z -score table.
00:47
I prefer not to unless told to because there's a risk of rounding errors using that.
00:52
Or you could use technology.
00:54
Some kind of software like excel or r, i'm going to use my ti -84 calculator with the normal cdf function.
01:03
This has four inputs, a lower bound, an upper bound, a mean, a standard deviation.
01:09
It gives you the area between the lower and upper bounds on this particular normal curve...