Answer:
21.5
Step-by-step explanation:
Arrange numbers from smallest to largest:
56, 65, 69, 77, 79, 82, 88, 89, 90
The interquartile range is the range in the middle of the data set, we can find it by knowing the upper and lower quartiles.
56, 65, 69, 77, 79, 82, 88, 89, 90
(65+69)/2 = 67
(88+89)/2 = 88.5
The interquartile range:
88.5 - 67
= 21.5
