Find the Percentile

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.