Question

What are the minimum, first quartile, median, third quartile, and maximum of the data set? 9, 20, 4, 18, 4, 18, 20, 9

Answer 1

put them in order... minimum will be the first, median the middle, maximum the last
not sure what you mean by quartile but I am sure you will figure it out

Answer 2

quartile is 1/4
first quartile is 25% of data, third quartile is 75%

Answer 3

As philips13 mentioned, arrange them in order first
9, 20, 4, 18, 4, 18, 20, 9 => 4, 4, 9, 9, 18, 18, 20, 20
from that you can get the minimum and the maximum.

Then there are 8 terms
Median = average of 4th and the 5th term = do it yourself
1st quartile = average of 2nd and the 3rd term = do it yourself
3rd quartile = average of 6th and the 7th term = do it yourself