in the data set below, what is the interquartile range? 2 3 5 5 7 7 9 9

Answer:

4

Explanation:

Step1: Arrange data in order

2, 3, 5, 5, 7, 7, 9, 9

Step2: Find median (Q2)

Since there are 8 data - points, the median is the average of the 4th and 5th values. $\frac{5 + 7}{2}=6$.

Step3: Find Q1

The lower half of the data is 2, 3, 5, 5. The median of this lower - half (Q1) is $\frac{3+5}{2}=4$.

Step4: Find Q3

The upper half of the data is 7, 7, 9, 9. The median of this upper - half (Q3) is $\frac{7 + 9}{2}=8$.

Step5: Calculate inter - quartile range (IQR)

$IQR=Q3 - Q1=8 - 4 = 4$.