The following stem-and-leaf plot represents the times in minutes required for 26 co-workers to commute to work. Use the data provided to find the quartiles.
Commute Times in Minutes
Stem Leaves
1 0 4 4 6 6 6 9
2 2 4 4 5 8
3 3 4 4 5 6 8
4 0 0 3 3 5 6 7 8
Key: 1|0=10
Step 2 of 3 : Find the first quartile.
To find the first quartile (Q1), we need to find the median of the lower half of the data set.
The lower half of the data set includes the values from 10 to 38 minutes.
- 10, 14, 14, 16, 16, 18, 22, 24, 24, 24, 25, 28, 33, 34, 34, 35, 36, 38
There are a total of 18 values in the lower half of the data set.
Since there is an even number of values in the lower half, the median is the average of the middle two values.
The 9th and 10th values are 24 and 24.
So, Q1 = (24 + 24) / 2 = 24.
Therefore, the first quartile (Q1) is 24 minutes.