## Convert Raw Scores to Cumulative Percentages

**Step 3: Compute the Cumulative Frequency.**

The next step is to compute the cumulative frequency (*cf*). In order to do this, look at the numbers that were entered into the
frequency (*f*) column and add them up. 2+7+3+1+2=15. This will give you the number of scores that are *at* or *below* the X value
of 99. Place the number 15 in the column labeled *cf*. (Note: The highest score in the X column will equal *cf*=∑*f*. In this
case, cf=∑*f* corresponds to X=99. Because all of the scores in the distribution are at or below X=99; X=99 also corresponds
to the 100th percentile.)

To determine the cumulative frequency (*cf*) of X=80, add together the numbers in the *f* column beneath 7 and include 7. For example,
add 7+3+1+2=13. Record 13 in the *cf *column across from X=80.

Next find the cumulative frequency (*cf*) for X=60. Now you will add together 3+1+2=6. Record 6 in the chart below *cf* across from X=60.

Next, find the frequency of X=59. In order to do this, add 1+2=3 and enter 3 in the column under *cf* across from X=59.

Next, find the frequency of X=25. X=25 occurs 2 times. Therefore, the frequency of X=25 is 2. Record 2 in the column under *cf* across from X=25.

Continue to Step 4: Compute the Cumulative Percentage.

Copyright 2005 by the Student Success Center and the University of Houston-Victoria.

Created 2004 by Maranda Koenig. Content Reviewed by Hari Damodaran. Edited by Sandra Heinold.