Consider a sample with data values of 10, 20, 12, 17, and 16. Compute the...

The range is the difference between the largest and the smallest value:
RANGE =20-10=10
The first quartile is the median of the data values below the median (or at 25% of the data):
${\displaystyle Q_1=\frac{10+12}{2}=11}$
The third quartline is the median of the data values above the median (or at 75% of the data):
${\displaystyle Q_3=\frac{17+20}{2}=18.5}$
The interquartile range IQR is the difference of the third and first quartile:
${\displaystyle IQR=Q_3-Q_1=18.5-11=7.5}$
Results:
RANGE=10
IQR=7.5