Quartiles are special numbers that help us break up a set of data into four equal parts. There are three main quartiles: Q1, Q2, and Q3. These quartiles help us understand how the data is spread out.

Here’s what each quartile means:

• Q1: This is the point where 25% of the data is below it.
• Q2: This is the middle point, or the median, where 50% of the data is below it.
• Q3: This is where 75% of the data is below it.

When we use box plots to look at data, quartiles help us see things easily. The box in a box plot shows the interquartile range (IQR), which is the space between Q1 and Q3. There’s also a line inside the box that shows Q2.

Example:
Let’s take the data set: {1, 3, 7, 8, 9}.

• For this set, we see that Q1 is 3, Q2 is 7, and Q3 is 8.

These quartiles show us how the data is spread out and where the center is!