00:01
We've been given an incomplete table.
00:03
So this is the number of times per week people flops.
00:07
Okay, so we have x, the possible values, their frequency, their relative frequency, the cumulative frequency.
00:18
Okay, so to go from frequency to relative frequency, all you need to do is frequency over the total number of people n.
00:29
So relative frequency is the proportion of the total made up by that group.
00:35
Cumulative frequency is a running total.
00:39
It's the number of people in this class or in previous ones.
00:44
So if you look at the cumulative frequency for 7 times per week, 130, that's the number of people who floss 7 times a week or fewer, aka everybody, all 130 of them.
00:58
So we need some values, we need the frequency for 2.
01:02
Okay, i can see that the relative frequency is 0 .2, so that means 20 % of these 130 people met that criteria, that's 26.
01:13
It's also the value you add on to 35, the previous cumulative frequency, to get 61.
01:21
We need the cumulative frequency of 4.
01:27
So this is whatever you get when you add the previous one, 72, to the frequency for 4, 19...