00:01
We have a frequency table here.
00:02
In part 8, we have to identify the values of a and b.
00:07
So these are the sums of fm and fm squared.
00:14
So we have all of the values, we just have to add them up.
00:18
So we're going to get the sum.
00:22
Okay, so let's start with fm.
00:24
So we've got 3 plus 18 plus 50 50 plus 28 plus 18 is 117.
00:38
For the next column we have 3 plus 54 plus 250 plus 196 plus 162, giving us some 665.
00:57
Question 9.
00:58
A kitten has a mass under 2 kilograms.
01:02
What percentage of kittens fall into that group.
01:06
Okay, so if we look at the frequency of the class we're looking at, under 2, there are 3 kittens there.
01:12
3 out of 25.
01:14
The sum of all the frequencies is 25.
01:17
So we have 25 kittens in the sample, and 3 of them meet this criteria.
01:21
This is the fraction that meets the criteria.
01:24
If i divide this, 3 over 25, i get the proportion, 0 .12.
01:30
If i multiply by 100, i get the percentage.
01:32
12 % of these kittens meet that criteria.
01:36
Option a.
01:39
Question 10.
01:40
Now we want to get the mean.
01:44
So we have some information here.
01:47
So you get the mean of a data set, x bar for sample mean.
01:51
You take each value, you add them up, you divide by the total.
01:57
That's the simplest way of putting it, but there's a couple of complications here.
02:01
First of all, it's a frequency table.
02:03
We don't just have a list of values.
02:04
That's fine.
02:05
We can just multiply by frequency.
02:08
It's just like adding f number of pieces of data of that type...