Consider frank's math test scores for the semester. find the interquartile range of the scores.

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.