How do you find the IQR in Math?

Question

I need to find the IQR of a question that is due tomorrow, can you help?

Answer 1

As an example, let's say you're given the data set 7, 6, 9, 5, 1, 2, 3, 3.

 

To find the IQR, you'll first need to put your data in order from lowest to highest:

 

1, 2, 3, 3, 5, 6, 7, 9

 

Next, find the median (middle number). This value is called Q2 (Quartile 2).

 

2, 3, 3, 5, 6, 7

 

Since there is no middle number, we use the average of the two middle numbers. (3+5)/2 = 8/2 = 4.

 

The median divides the data set into two halves: 2, 3, 3 and 5, 6, 7. Now, we'll basically find the median of each of the halves. The lower half's median is called Q1 (Quartile 1), and the upper half's median is called Q3 (Quartile 3).

 

2, 3, 3 and 5, 6, 7

 

For this data set, Q1 = 3 and Q3 = 6. The IQR (Interquartile Range) is just the difference between Q1 and Q3. In other words:

 

IQR = Q3 - Q1 = 6 - 3 = 3