00:01
So here we're given a frequency table for a sample of size 30.
00:06
And looking at these class sizes, the minimum value between 20 and 27, those classes, the difference is 7.
00:21
And then if i let a, b, 27 plus 7, that will be 34.
00:29
Then the next lower bound would be 34 plus 7 which is 41 so that matches and then b is going to be 41 plus 7 again which is 48 and then 48 plus 7 is 55 so the class size here is 7 and that is what we add to these boundaries to find a and b then because our class size is 7 the midpoint c is just going to be the previous midpoint 23 .5 plus 7, which is 30 .5.
01:04
D is going to be 30 .5 plus 7, which is 37 .5.
01:11
And e is going to be 44 .5 plus 7, which is 51 .5.
01:19
And then the other missing value is f, which is going to be 30 minus 7 minus 6, minus 5, minus 3 minus 1 and which then is equal to 8 so let's see here this is 30 .5 37 .5 51 .5 8 and then we also want to know the 85th percentile of a sample of size 30 well that is going to be then the 0 .85 times 30 is 25 .5.
02:22
So the 25th, between the 25th and 26 value.
02:29
And if you look here, then that means that there will be 25 values below.
02:39
The 85th percentile and four values above...