00:01
You have a stem and leaf display of some data set, and our first goal is to calculate the fourth spread.
00:09
And then we want to construct a box -in -whisker plot.
00:12
So what we're going to do here is we're going to find the five -number summary first.
00:24
And the five -number summary includes the minimum, the lower -fourth boundary, and sometimes that's represented as quartile one, the median, that is often referenced as quartile two.
00:59
The upper fourth boundary, oftentimes referenced as quartile three, and the maximum.
01:19
So we're dividing this data set into fourths.
01:23
And if you count up how many there were, there were 44.
01:28
So that means halfway would be 22.
01:34
So the halfway point would be right here.
01:38
There's 22 numbers or values before that line, there are 22 values after that line.
01:45
And then if we divide up the first 22, that means there would be 11 in front of this line and 11 after that line.
01:58
And then if we break the upper half into halves, we would have 11 before this line and 11 after that line.
02:10
So therefore, our five number summary, we have a minimum value of 32 .1.
02:20
We have a lower fourth quarter boundary by averaging these two values together.
02:28
So if i average 35 .8 and 35 .8, i will get 35 .8.
02:37
The median is the middle number.
02:40
So that means i have to average these two values together.
02:44
So if i average 36 .8 with 37 .2, i will get 37.
02:54
The upper fourth boundary, i need to average these two values together, and i will get 39 .55, and then the maximum value is 42 .9.
03:13
So i'm now ready to talk about the fourth...