Answer:
IQR = 8
Step-by-step explanation:
the IQR is the difference between the upper quartile Q₃ and the lower quartile Q₁
first step is to find the median Q₂
the median is the middle value of the data arranged in ascending order. If there is no exact middle value then it is the average of the 2 values either side of the middle.
4 4 6 7 10 11 12 14 15
↑ middle value Q₂ = 10
the lower quartile is the middle value of the data to the left of the median
4 4 6 7
↑ Q₁ = (4 + 6) ÷ 2 = 10 ÷ 2 = 5
the upper quartile is the middle value of the data to the right of the median
11 12 14 15
↑ Q₃ = (12 + 14) ÷ 2 = 26 ÷ 2 = 13
then
IQR = Q₃ - Q₁ = 13 - 5 = 8
