Which one of the values below represents a lower quartile for the data set 23, 24, 21, and 20?
A) 22.0
B) 22.5
C) 20.25
D) 23.5
E) none of these

Question

Quizplus · Accepted Answer

To find the lower quartile, we need to arrange the data set in order from least to greatest: 20, 21, 23, 24. The median of the lower half of the data set is the lower quartile. The lower half of the data set is 20 and 21. The median of 20 and 21 is (20+21)/2 = 20.5. Therefore, the lower quartile is 20.5, which is closest to choice C (20.25).

Which One of the Values Below Represents a Lower Quartile