The owner of a coffee shop recorded the number of customers who came into his café each hour in a day. The results were 14, 10, 12, 9, 17, 5, 8, 9, 14, 10, and 11. Find the lower quartile and upper quartile of the data.

Answer 1

To find the lower quartile (Q1) and upper quartile (Q3) of the data, we first need to arrange the data in ascending order:
5, 8, 9, 9, 10, 10, 11, 12, 14, 14, 17

To find Q1 and Q3, we will use the formula:
Q1 = (n + 1) / 4
Q3 = 3 * (n + 1) / 4

where n is the number of data points, which in this case is 11.

Q1 = (11 + 1) / 4 = 3rd data point
Q1 = 3rd data point = 9

Q3 = 3 * (11 + 1) / 4 = 9th data point
Q3 = 9th data point = 14

Therefore, the lower quartile (Q1) is 9 and the upper quartile (Q3) is 14.