Calculate percentile rank

Question

I am confused with the concept of percentile rank. I am in the top 7 of my class, how would I calculate my percentile rank?

Number of students 72 I am 7th rank in my class

Does this mean my percentile rank is 7?

Answer 1

You are in the top $\frac7{72}\times100\% \approx 10\%$ of your class. Since percentile rank is usually expressed in terms of "how many percent are worse or equal to the score in questions", that means your percentile rank is $90$.

Answer 2

The $7^{th}$ best rank is the $\color{blue}{66}^{th}$ data item in the ordered $72$ scores.

So, this is the $\color{blue}{91^{st}}$ percentile as $\left \lceil 72\cdot \frac{\color{blue}{91}}{100} \right \rceil = \color{blue}{66}$.

Note, that it is not the $92^{th}$ percentile as $72\cdot \frac{92}{100} > 66$.