Dustin Project

Percentile ranks are statistics which tell the reader that the student scored “as well as or better than” other members in the testing pool.

Percentile ranks can NEVER be more than 99PR.

To find the percentile rank of a given score, the score must first be converted to a z-score and then “looked up” on a statistical table.

Fortunately, the World Wide Web has many helpful tools to do these things for us.

Step 1: Using the mean and standard deviation for your distribution, find the z score.

Point your browser to: https://www.danielsoper.com/statcalc/calculator.aspx?id=22

Enter the Mean, Standard Deviation, and the Score of Interest (Value).

Hit “calculate!”

The blue number is your z score.

Highlight this number and “copy” it onto your “clipboard.”

Step 2: Find the z score’s associated Percentile Rank.

Point your browser to: https://measuringu.com/calculators/pcalcz/

Click in the z-score box.

Paste the z score into this box.

Make sure that the options are set to “two-sided” and “Decimal Points: 4.” Click “submit.”

The “number” you want is “Percent of Area.” This is the score’s percentile rank.