Lesson 5

Lesson 5 Summary

 

In this lesson you investigated the following questions:

• How can percentiles be used to help guide decisions?
• What is the difference between percent and percentile rank?

It is often useful to know how a value compares to others in a data set. This can be done through percentile rank scoring. Calculating percentile rank also allows you to compare sets of data of varying sizes more easily. In the case of the crash test dummies, now you understand that the 50th percentile male is an average sized male, the 5th percentile female is a small female, and the 95th percentile male is a large male.

 

The 50th percentile is also known as the median because 50% of the data lies below the median.

 

Percentile rank is calculated as shown, where b is the number of values below the one being considered and n is the total number of values in the data set.