Question 894:

Asked on July 17, 2011

Tags: Z-Score

1

Answer:

No answer provided yet.Yes. A percentage can be converted to a z-score by using the area under the normal curve. If we think of the area under the normal curve as representing 100% of the area, we can find the z-score that's associated with a specific percentage, for example 20% or 95%.

To do so you can use a z-table or an online calculator. You need a calculator or table because to find areas under curvy shapes you need to use calculus--which can be rather tedious.

So for example, by entering in .20 in the calculator we get the z-score of -1.28 and we get 1.96 when we enter .95.