Answer:
Percentile of 20th = 20
Percentile of 25th = 22.5
Percentile of 65th = 28
Percentile of 75th = 29
Explanation:
Sort the numbers in ascending order:
15,20,25,25,27,28,30,34
i = P/100 * N ( i index is the position of the number. Index 1 = 15, index 2 = 20, and so on)
Index of the 20th percentile:
20/100 * 8 = 1.6
Round 1.6 to the next integer = 2
The second number I=20
The 20th percentile is 20
Index of the 25th percentile:
25/100 * 8 = 2
Because 2 is an integer the percentile of 25th is the average of I=20 and I=25
(20+25)/2=22.5
The 25th percentile is 22.5
Index of the 65th percentile
i = 65/100 * 8 = 26.5 = 5.2
Round to the next integer = 6
The 65th percentile is 28
Index of the 75th percentile
I = 75/100 * 8 = 6
Since 6 is an integer (28+30)/2 = 29 percentile
