00:01
To begin this problem, i'm going to start by, i already divided the page into three sections, and i'm going to label each one to show the different categories that we have going on in this problem.
00:13
So, you know, there's an age group of 18 to 34.
00:17
There's another age group from 35 to 44.
00:23
And the last age group we're looking at is in the 45 and up.
00:28
So we're going to find the mean, the sample variance, and the, sample standard deviation for all three of these age groups.
00:37
Now the number, all the numbers and the graphs that we're using are all given to us so you can look at that because that's necessary.
00:45
So first start looking at the column that shows all of the 18 to 34 numbers or data points.
00:54
And what you're going to do is i know that it starts with 1 ,335 goes to 115 and goes all the wide down has 10 numbers in total.
01:05
It ends with 1390 i believe and the first thing you want to do is you're going to total all of the numbers that are in the column from 18 to 34 with that age group you're going to total it up and you should get one three 13 ,680 as your total this is your total you can do the same thing for the 35 to 44 i believe begins with 969 it goes 434 and so on.
01:36
It has 10 numbers.
01:37
It ends with 14, 15.
01:39
And you're going to total all 10 numbers up that are given to you.
01:43
And you should get 13 ,301.
01:47
And that's a total.
01:49
And same thing for 45 and up.
01:52
This is what it begins with.
01:56
It keeps going and going 10 numbers worth.
01:58
And then ends in 1510.
02:02
And the total is 10 ,704.
02:10
Did was add the columns up of data.
02:12
So let's start with the age group of 18 to 34.
02:16
We want to find the first thing which is mean.
02:20
So how you find mean is with this expression, the sum of x over how many numbers there are.
02:29
We just found the sum of x, that's what we did.
02:32
We added up all the numbers in the column.
02:34
And we got 13 ,680.
02:38
And we're told there's some numbers.
02:41
We say that there's 10 consumers we're selected.
02:44
So we know that there's 10, but we can also just count how many x's there are, and we can see that there's 10.
02:50
So with this, we know we can learn that our mean is 1 ,368.
02:57
And that is the answer for mean.
02:59
We're going to do the same thing over here.
03:03
Using the same equation, e of x, we learned is 13 ,301.
03:09
It's the same amount of numbers, so it's 10.
03:11
You're dividing it and you should get 1 ,330 .1 as your mean.
03:21
And then lastly over here, 10 ,704 divided by 10, and you get 1 ,0704.
03:33
So first step of finding the mean is completed and done.
03:37
Now we need to know the sample variance.
03:41
So i'm just going to write s.
03:46
Variance.
03:48
So the equation for this looks like this.
03:51
It's mean the sum of one number minus the mean, which we just found, squared over n minus one.
04:05
So if you know how to, if you know what these represent, you should be able to figure it out because x of i is going to be every single one of these numbers...