Hi,
In “I’m Overwhelmed” Module 10 part 3, Greg says that quartiles are distinct groups wherein the 3rd quartile basically includes a quarter of the data; the ones higher than the median and lower than Q3.
However, I believe that Q3 is one value that has 75% of all the data below it.
So, Q1, Q2, Q3, and Q4 are not groups, they’re just values that have a percentage of the data below them. If that’s the right, then the video is a bit misleading.
You’re correct in that Q1, Q2 (the median), and Q3 are specific values that divide the data into quartiles, and each has a percentage of the data below it.
Q3, for example, is the value where 75% of the data falls below. However, when Greg refers to “quartiles” as groups, he’s talking about how the data is divided into four distinct sections based on those values.
So, the 3rd quartile refers to the data points that lie between the median (Q2) and Q3. It’s a common way of explaining how the data is split, even though the quartiles themselves are just the dividing points.