Book Image

Minitab Cookbook

By : Isaac A Newton
Book Image

Minitab Cookbook

By: Isaac A Newton

Overview of this book

Table of Contents (19 chapters)
Minitab Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Testing for equal variances


In this recipe, we will return to the topic of atmospheric pressure data. The data was obtained from the Climactic Research Unit. We will look at the atmospheric pressure recorded at the Gibraltar weather station. The test for equal variances will be used to check for differences in variance by month.

As with the data for the pressure difference used in the example, using the one-way ANOVA with unstacked columns' missing values is coded as -10. We will recode these to *. We will also need to stack the data before checking for differences in variation between the months.

Getting ready

Either open the file nao_gib.dat using the Open Worksheet command in Minitab or copy the data to Minitab from the NAO website. If opening the worksheet, set the file type to *.dat. Then use the Options file to set the Variable Names option to None and the Field Definition option to Free Format.

This nao_gib.dat file is also available on the Packt Publishing website.

How to do it…

The following...