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

Put the numbers in order...
4,5,6,6,7,8,9,9,10,10,12,12,14,15

Q1 = (6 + 6) / 2 = 12/2 = 6
Q2 (median) = (9 + 9)/2 = 18/2 = 9
Q3 = (12 + 12) / 2 = 24/2 = 12

Q3 - Q1 = 12 - 6 = 6 (this is actually the interquartile range (IQR)

Answer 2

Here, just arrange the numbers in chronological order:
4, 5, 6, 6, 7, 8, 9, 9, 10, 10, 12, 12, 14, 15

Now, median = 9

1st quartile = [4, 5, 6, 6, 7, 8]
3rd quartile = [9, 9, 10, 10, 12, 12, 14, 15]

Q1 = 6+6/2 = 6
Q2 = 10+12 / 2 = 11

So, Q2 - Q1 = 11 - 6 = 5

In short, Your Answer would be 5

Hope this helps!