Here's 4
24 18 29 21 16 23 13 11
First step...order the data from lowest to highest
11 13 16 18 21 23 24 29
Find the median of the data = (18 + 21)/2 = 39/2 = 19.5 = Q2
Find Q1 = (13+16) / 2 = 29/2 = 14.5
Find Q3 = (23 + 24)/2 = 47/2 = 23.5
The first answer is correct
5. This is pretty easy, NSS........
18 9 7 5 11 7 17 20 19 2 17 12 5 1 13 12 11 15 16 20
Order data from low-to-high...there are 20 values
1 2 5 5 7 7 9 11 11 12 12 13 15 16 17 17 18 19 20 20
To find the 30th percentile....multiply .30 * 20 = 6 (this is the index)
The 6th number in the data set is 7
Similary...to find the 90th percentile......multiply .90 * 20 = 18 (this is the index )
The 18th number in the data set is 19
So.....the first answer is correct
(BTW....there may be several other acceptable ways to do this )