Question

Given the following dataset, what is the first quartile? Round to the nearest tenth if necessary.
42, 82, 67, 34, 54, 62, 17, 47, 56, 18, 20

Answer 1

First sort the data: 17, 18, 20, 34, 42, 47, 54, 56, 62, 67, 82.

With 11 values the median is the 6th value (47). The lower half (excluding the median) is 17, 18, 20, 34, 42; the median of that lower half (the 3rd value) is 20.

So the first quartile Q1 = 20.