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
18 the answer is 18
To find the first quartile, we need to first order the data set from smallest to largest:
17, 18, 20, 34, 42, 47, 54, 56, 62, 67, 82
Now we divide the data set into two halves. The first half is:
17, 18, 20, 34, 42
Since there are 5 data points in this half, the median (second quartile) is the middle value, which is 20. Now we need to find the median of the first half of the dataset, which is:
17, 18, 20
Since there are 3 data points in this half, the median (first quartile) is the middle value, which is 18. Therefore, the first quartile is 18.