Question

Which value is not part of the five-number summary needed for a box plot of this data?

Answer 1

In this sequence 1,2, 5,6,7,9,12,15,18,19,27 . The median is 9 . The 1st quartile is 5  while the  3rd quartile is 18. Maximum number is 27 and the minimum number is 1. Therefore the answer is D which is 11. 

Answer 2

Order the row {5, 6, 1, 27, 2, 7, 12, 15, 9, 18, 19} from the smallest number to the biggest number:

{1, 2, 5, 6, 7, 9, 12, 15, 18, 19, 27}.

The minimum is 1, the maximum is - 27.

The median is the middle number in this row - 9.

The median of left part {1, 2, 5, 6, 7} is 5 and the median of the right part {12, 15, 18, 19, 27} is 18.

From the option A-D only number 11 is absent (numbers 1, 5 and 9 are part of the five-number summary).

Answer: correct choice is D.