00:01
So we have a sample size of 64 taken from a normal population.
00:05
So we'll have a new sampling distribution with a mean still at 51 .4, but the standard deviation of 6 .8 changes.
00:13
It changes, you divide it by the square root of the sample size right here.
00:18
So that standard deviation gets smaller, the distribution gets a little more narrow as we answer these.
00:24
So there's three situations, a greater than, a between, and a less than.
00:28
So for a, we're talking about a greater than or exceeding value 52 .9.
00:33
If you look at the picture, i've got the mean there situated at 51 .4, and then we need to get a z -score standardized.
00:41
So we put in the 52 .9, which was the x value they gave us, minus the mean divided by the new standard deviation, and you get 1 .76 for the z -score for this spot right here.
00:56
Since it's exceeding, we want to go to the right.
00:58
There's two different ways to get that probability or the area under the curve.
01:03
You can use a z -table, and you take that, you look up 1 .76, and you're going to go one minus that because it's the right side.
01:11
Or you can use a calculator, and you just put in two values, the z -score, and then something very large...