Question

What is the purpose of calculating z-scores?

Answer 1

`z` score is calculated to make a Normal Distribution into a Normal Probability Distribution.

Explanation:

We a innumerable number of Normal Distributions. Each can be identified by its Mean and Standard Deviation.

They all posses the same characteristic feature, They cannot be used in the inferential statistics to make in prediction about population parameter and hypotheses testing.

Once a Normal Distribution is converted into a Standard Normal Distribution, its mean becomes 0 and its standard deviation becomes 1 irrespective of the original distribution's Mean and Standard Deviation. Area under the curve represents Total Probability. It is equal to one.

Ultimately it becomes an analytical tool in the hands of statisticians.

Please watch these viedo lessons