22. The following frequency distributionpresents a set of exam scores for a class of N=20 students.

x f cf c%

90-99 4 20 100

80-89 7 16 80

70-79 4 9 45

60-69 3 5 25

50-59 2 2 10

a. find the 30th percentile.

b. find the 88th percentile.

c. What is the percentile rank for x=77?

d. What is the percentile rank for x=90?

Note: Please find the solution in the attached word document. The solution given here is for your reference.

Solution:

a. Percentile is given by the formula,

P = L +

Here L- Lower class boundary of the selected class interval

n- Number of observations in the data

cf- Cumulative frequency below the selected class …

The solution solves percentiles in a class of students.