00:01
In this question, we have some sample data.
00:03
We want the margin of error for a confidence interval for the population mean.
00:07
Now, the formula for this interval is x bar, point estimate, sample mean, plus minus the margin of error, z sigma, over root n.
00:17
So this is a formula that you should have in a formula list, or you can memorize these.
00:23
You probably should.
00:24
This is a very common one.
00:25
Now, the only thing to keep in mind is what kind of critical value you use.
00:30
The z and there's t.
00:32
We're using z because sigma is no.
00:35
If we only had the sample standard deviation, i would be using a t here.
00:40
It would be ts over root n.
00:42
But since we know sigma, we're going to use that.
00:45
In fact, we don't need the raw values at all.
00:47
We need the sample size, 5.
00:49
The sample mean 16 .5, and the population standard deviation 1 .25...