Okay so you put the numbers in order:
70, 74, 81, 82, 83, 91, 94.
Then you find the median which will be Q2:
82.
Once you have the total median, you find the midpoint of the first and last part:
70, 74, 81. Midpoint/Q1=74
83, 91, 94. Midpoint/Q3=91
Now that you have that, you subtract Q3 and Q1.
91-74=17
17 is your IQR.
