00:01
For this problem, we were told that the data, which i've copied into excel over on the side here, gives the weekly amounts spent on groceries for a sample of households.
00:09
In part a, we were asked, how many classes would we recommend? so, one second here, things might look a little weird for a second.
00:16
Okay.
00:17
So, the number of classes would be n, or pardon me, it would be k, such that 2 to the power of k is greater than or equal to n.
00:31
The number of samples.
00:33
So we can see that we want 2 to the power of k to be greater than or equal to 45.
00:41
So 2 to the power of, let's say 6, 2 to the power of 6 is 64, 2 to the power of 5, oops, 2 to the power of 5 is 32.
00:53
So that means that we need k should be equal to 6, or that we should have six different classes.
01:02
Then we're asked, what class interval would we suggest? well, we want to find that by first finding the range of our data.
01:10
So we should be able to do equals one moment here.
01:17
So we want to do equals max of our data set minus the minimum value of the dataset.
01:27
So the range is, we find that the range is 595.
01:33
So the interval is going to be roughly the range, 595, over the width, or over the number of intervals, or number of classes, i should say.
01:49
So we'll approximate that interval of roughly 99 to, let's round that to an interval of 100.
01:59
Then we're asked, what would we recommend as the lower limit of the first class? so let's first find what the minimum value is.
02:09
So the minimum value of our data set equal to 22.
02:14
So the lower limit of the first class, we can say that that should be $0.
02:21
Then we're asked to organize the data into a frequency distribution.
02:25
So i'm using excel here.
02:27
One way that we can do this would be to select the data.
02:30
Then we want to go to, it's going to be pivot table, create a new pivot.
02:37
Here.
02:39
We want to select all of that.
02:43
Oops, now i don't want to create a new pivot table, but what to change what the value is here.
02:51
One moment.
02:52
So actually, i'm just going to make a slight change.
02:55
I'm going to add in a new data point at the very top of our data.
03:05
Copy and paste this one down below.
03:07
Oops...