Question

This data set represents the number of cups of coffee sold in a café between 8 a.m. and 10 a.m. every day for 14 days.

Answer 1

The answer to your problem is, The difference of the values of the first and third quartiles of the data set is 12 - 6 = 6

Explanation:

Numbers in order:

4,5,6,6,7,8,9,9,10,10,12,12,14,15

List into two equal parts:

4,5,6,6,7,8,9 and 9,10,10,12,12,14,15

Find middle numbers:

4,5,6,6,7,8,9 and 9,10,10,12,12,14,15

Lower quartile: 6

Upper quartile: 12

Thus the answer to your problem is, The difference of the values of the first and third quartiles of the data set is 12 - 6 = 6