Normality of difference scores
Normality of difference scores means differences between observations must be normally distributed
In most instances, if the distribution of each observation of the outcome is normally distributed (skewness and kurtosis statistics above an absolute value of 2.0), then the assumption of normality of difference scores will be met. However, in order to be thorough and account for any inconsistencies in the data, subtract each observation from the other observations and run skewness and kurtosis statistics on the difference scores yielded to ensure that this assumption is met.
The assumption of normality of difference scores is assessed when using repeated-measures t-tests and repeated-measures ANOVA. Click on the buttons below to learn how to test for these assumptions in SPSS.
Normality of difference scores and applied statistics
Statistician Services for Students
Eric Heidel, Ph.D. will provide the following services for undergraduate and graduate students at $50/hour. Secure checkout is available with Stripe or PayPal.
- Statistical Analysis
- Research Design
- Sample Size Calculations
- Diagnostic Testing and Epidemiological Calculations
- Survey Design and Psychometrics
AppNotch: Convert this website into an Android and iOS app.
AppNotch team will notify you when your app gets approved in Google Play and Apple iTunes App Stores. Once your app goes live, enter your App Store URLs in this property window, publish your Weebly site and your app store icons will be visible in this page.
Please visit AppNotch.com FAQ to learn more about how to add App Store icons to your website, update your app, send Push notifications and more.
Professional Statistician For Hire!
Copyright © 2017 Scalë. All Rights Reserved. Patent Pending.