00:02
Hello, so we've been given this set of data.
00:08
We want to first find the sample mean.
00:12
This is the summation of x divided by n.
00:17
N is the number of numbers we have in here.
00:24
So if you add all these numbers we're going to get 369 and then we have 12 of those.
00:32
So our mean is going to be 30 .75.
00:40
So that's the first part.
00:42
Now if we want to find the confidence interval we need to find the standard division.
00:51
So the standard division, so here we can use, let's look at standard division using excel.
01:07
So we can just use excel and just type in equal to and then do stdev .s as the standard division of the sample and then input all these numbers.
01:26
So we have 21, 27, 35, 42, 31, 39, 28, 34, 23, 35, 20, 25.
01:50
Okay, so you just hit enter and you're going to have your standard division come out to be 6 .89.
01:57
So once we have that, let's talk about finding the, so we start with the 95 % confidence interval...