00:01
Ok, we have here a normal curve.
00:03
So the usual bell -shaped distribution, like this.
00:09
Here is x.
00:11
The mean in the middle, as always, is 18 .5 in this case.
00:17
And symmetry about the mean, time deviation, 3 .25.
00:23
But the key thing about a normal curve is the area underneath here is always going to be 1.
00:28
That green area is 1.
00:31
I want to work out in this question, first of all, the chance of being 16 or below.
00:43
It simply means find the area below 16.
00:47
I want to find this area here.
00:51
And to find the area of a normal curve, use the function called normalcdf, which you will find on the ti -84 plus, for example, by pressing 2nd followed by vars, v -a -r -s, on the right by the arrow keys.
01:13
That gives the menu for distribution.
01:16
Number 2 on the list is normalcdf.
01:18
So choose that and press enter.
01:21
It's a four number input...