Question

An instructor wants to compare final grades of students in her online class and face-to-face class. Instructor selects 10 students randomly from each class and the following table shows the final grades of those students.

5.5
7
6
7
6.5
6
9
6.5
6.5
6.5

The 81st percentile of time students sleep per night is ______hours.

Answer 1

7 hours

Explanation:

The formular of percentile is given as;

n = (P / 100) * N

where;

n = ordinal rank

P = Percentile

N = Number of values

The grades are given as;

5.5, 7, 6, 7, 6.5, 6, 9 , 6.5, 6.5 , 6.5

Arranging in increasing order;

5.5, 6, 6, 6.5, 6.5, 6.5, 6.5, 7, 7, 9

n = (81/100) * 10 = 8.1 ≈ 8

The 81st percentile is the 8th term.

The 8th term = 7