changingminds.org

How we change what others think, feel, believe and do

| Menu | Quick | Books | Share | Search | Settings |

Sphericity

 

Explanations > Social ResearchAnalysis > Sphericity

Description | Discussion | See also

 

Description

If variance is equal across a number of treatments in an experiment, then the measurement is said to be 'spherical'.

In ANOVA and F-ratio calculations, it is assumed that the groups being tested are independent. If this is not the case, then the F-ratio will be inaccurate. Sphericity measures this independency by looking for relationships between variables.

Sphericity can be calculated via Mauchly's test (or Mauchly's W), which assesses the hypothesis that variances of the differences between conditions are equal. If the result of this test is significant (p < .05) then it can be concluded that some pairs of conditions are more related than others, and that the F-ratio is not reliable.

Discussion

The implication of non-sphericity is that Type 2 errors are more likely (which means power is reduced).

There are three corrections that can be used to adjust the F-ratio to be more valied and hence reduce Type 2 errors:

  • Greenhouse-Geisser estimate of sphericity
  • Huynh-Feldt estimate of sphericity
  • Lower-bound, lowest-possible estimate of sphericity

Each of these produces a correction factor for the F-statistic. The calculations and corrected F-ratio are all available through SPSS.

See also

F-ratio, ANOVA

Site Menu

| Home | Top | Quick Links | Settings |

Main sections: | Disciplines | Techniques | Principles | Explanations | Theories |

Other sections: | Blog! | Quotes | Guest articles | Analysis | Books | Help |

More pages: | Contact | Caveat | About | Students | Webmasters | Awards | Guestbook | Feedback | Sitemap | Changes |

Settings: | Computer layout | Mobile layout | Small font | Medium font | Large font | Translate |

 

You can buy books here

More Kindle books:

And the big
paperback book


Look inside

 

Please help and share:

 

Quick links

Disciplines

* Argument
* Brand management
* Change Management
* Coaching
* Communication
* Counseling
* Game Design
* Human Resources
* Job-finding
* Leadership
* Marketing
* Politics
* Propaganda
* Rhetoric
* Negotiation
* Psychoanalysis
* Sales
* Sociology
* Storytelling
* Teaching
* Warfare
* Workplace design

Techniques

* Assertiveness
* Body language
* Change techniques
* Closing techniques
* Conditioning
* Conversation
* Confidence tricks
* Conversion
* Creative techniques
* General techniques
* Happiness
* Hypnotism
* Interrogation
* Language
* Listening
* Negotiation tactics
* Objection handling
* Propaganda
* Problem-solving
* Public speaking
* Questioning
* Using repetition
* Resisting persuasion
* Self-development
* Sequential requests
* Storytelling
* Stress Management
* Tipping
* Using humor
* Willpower

Principles

* Principles

Explanations

* Behaviors
* Beliefs
* Brain stuff
* Conditioning
* Coping Mechanisms
* Critical Theory
* Culture
* Decisions
* Emotions
* Evolution
* Gender
* Games
* Groups
* Habit
* Identity
* Learning
* Meaning
* Memory
* Motivation
* Models
* Needs
* Personality
* Power
* Preferences
* Research
* Relationships
* SIFT Model
* Social Research
* Stress
* Trust
* Values

Theories

* Alphabetic list
* Theory types

And

About
Guest Articles
Blog!
Books
Changes
Contact
Guestbook
Quotes
Students
Webmasters

 

| Home | Top | Menu | Quick Links |

© Changing Works 2002-
Massive Content — Maximum Speed