How to find the IQR

Question

I'm trying to help my daughter with her math and I don't understand. 

 

The double plot shows the daily attendance for 2 fitness clubs for 1 month

 

Answer 1

You find the IQR by finding Q₃ and Q₁ for the data

 

The IQR is simply Q₃ - Q₁  

 

To find Q₁  find the median of the lower half of data

To find Q₃  find the median of the upper half of data

 

Sounds like this plot is a comparative stem and leaf plot

 

just do the IQR measurement for each side of the plot

 

 

For example:

 

1,2,3,4,5,    6,    7,8,9,10,11

 

In this problem Q₁ = 3    and  Q₃ = 9

 

Therefore the IQR would be 9 -3 = 6

 

IQR = 6