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.

{10, 9, 6, 12, 4, 6, 7, 8, 15, 14, 12, 9, 10, 5}.

The difference of the values of the first and third quartiles of the data set is
.

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)