Question

in the data set below, what is the interquartile range? 42 42 68 72 98

Explanation:

Step1: Arrange data in order

42, 42, 68, 72, 98

Step2: Find median (Q2)

Since there are 5 data - points, the median is the 3rd value. So, Q2 = 68.

Step3: Find lower half

The lower half is 42, 42. The median of the lower half (Q1) is 42.

Step4: Find upper half

The upper half is 72, 98. The median of the upper half (Q3) is $\frac{72 + 98}{2}=85$.

Step5: Calculate inter - quartile range

IQR=Q3 - Q1 = 85 - 42=30.

Answer:

30