Use this data set for all problems in this practice: 15, 12, 11, 16, 17, 12, 11, 17, 12
What are the lower quartile and upper quartile?
To find the lower quartile and upper quartile, you first need to arrange the data set in ascending order:
11, 11, 12, 12, 12, 15, 16, 17, 17
Next, calculate the median of the lower half and upper half of the data set.
Lower half: 11, 11, 12, 12
The median of the lower half is the average of the two middle numbers, which are 11 and 12. So, the lower quartile is (11+12)/2 = 11.5.
Upper half: 15, 16, 17, 17
The median of the upper half is the average of the two middle numbers, which are 16 and 17. So, the upper quartile is (16+17)/2 = 16.5.
Therefore, the lower quartile is 11.5 and the upper quartile is 16.5.