00:01
Let me take note the given values.
00:03
First of all, the population standard deviation given here, which was given as 5, and the sample size, so they're given 9 randomly selected student heights, which are, so the sample size is 9 here.
00:15
So, and the confidence level, here given as 99%, so what i need in order to get the sample, i mean the confidence interval for the population mean, i need the sample mean here.
00:27
Let's get the sample mean.
00:28
So for the sample mean, i'm going to add this 9 numbers together, 63 up to the last one here, which is 60, and divide this number by 9.
00:38
Let me do this by calculator.
00:40
This is 61, and then plus 63, 68, 63 plus 68 plus, and the next one, 61 plus 68, and plus 74, 63, 74 plus 63, and plus, so how many numbers do we have? 2, 4, 6, 7, okay, 63, and 73, and plus 60.
01:09
Here we go, and i'm gonna divide this number by 9, so the sample mean, 65 .67 here.
01:17
So first of all, let's get the margin of error.
01:20
So the margin of error, which is equal to, because we know the population standard division, so we have to use the z distribution here.
01:26
This is z alpha over 2, population standard division, divided by root n.
01:31
So the alpha is 1 confidence level, so we need alpha over 2, 1 minus 0 .99, divide by 2, which would be 0 .005.
01:40
So to get the z alpha over 2, i'm going to use the inverse norm function.
01:46
So the area was 0 .005, and the mean and the standard deviation...