Answer:
The first step on this case is order the dataset on increasing way, and after do this we got:
11 14 15 16 17 17 18 19 21
We have a sample size of n =9
And in order to find the 75th percentile we need to find the position for this percentile with this formula:

So then we can conclude that the 75th percentile would be approximately on the 7 position of the dataset ordered and we got:

Step-by-step explanation:
For this case we have the following data:
16 17 11 21 15 14 17 18 19
The first step on this case is order the dataset on increasing way, and after do this we got:
11 14 15 16 17 17 18 19 21
We have a sample size of n =9
And in order to find the 75th percentile we need to find the position for this percentile with this formula:

So then we can conclude that the 75th percentile would be approximately on the 7 position of the dataset ordered and we got:
