Answer:
30th percentile = 7
90th percentile = 19
Explanation:
Given : 18,9,7,5,11,7,17,20,19,2,17,12,5,1,13,12,11,15,16,20
To Find: Find the values of the 30th and 90th percentiles of the data.
Solution:
First arrange the data in the ascending order.
1,2,5,5,7,7,9,11,11,12,12,13,15,16,17,17,18,19,20,20
Now to find 30th percentile :
Since there are 20 numbers in data
So, 30% of 20 = 6
Thus the 6th number in the arranged list is the 30th percentile i.e. 7
Thus the 30th percentile is 7
Now to find 90th percentile :
90% of 20 =18
Thus the 18th number in the arranged list is the 90th percentile i.e. 19
Thus the 90th percentile is 19