Book Image

Mastering Python for Data Science

By : Samir Madhavan
Book Image

Mastering Python for Data Science

By: Samir Madhavan

Overview of this book

Table of Contents (19 chapters)
Mastering Python for Data Science
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
7
Estimating the Likelihood of Events
Index

Z-test vs T-test


We have already done a few Z-tests before where we validated our null hypothesis.

A T-distribution is similar to a Z-distribution—it is centered at zero and has a basic bell shape, but its shorter and flatter around the center than the Z-distribution.

The T-distributions' standard deviation is usually proportionally larger than the Z, because of which you see the fatter tails on each side.

The t distribution is usually used to analyze the population when the sample is small.

The Z-test is used to compare the population mean against a sample or compare the population mean of two distributions with a sample size greater than 30. An example of a Z-test would be comparing the heights of men from different ethnicity groups.

The T-test is used to compare the population mean against a sample, or compare the population mean of two distributions with a sample size less than 30, and when you don't know the population's standard deviation.

Let's do a T-test on two classes that are given...