What does significant greenhouse-Geisser mean?
What does significant greenhouse-Geisser mean?
What does significant greenhouse-Geisser mean?
The Greenhouse-Geisser is used to assess the change in a continuous outcome with three or more observations across time or within-subjects. When the assumption of sphericity is violated with repeated-measures ANOVA, then the Greenhouse-Geisser correction is used.
Should I use greenhouse-Geisser and Huynh Feldt?
When ε ≤ 0.75 (or you don’t know what the value for the statistic is), use the Greenhouse-Geisser correction. This is a conservative correction that increases the risk of Type II error. When ε > 0.75, use the Huynh-Feldt correction.
What is sphericity assumption in ANOVA?
Sphericity is an important assumption of a repeated-measures ANOVA. It is the condition where the variances of the differences between all possible pairs of within-subject conditions (i.e., levels of the independent variable) are equal.
When might you use the greenhouse Geisser correction?
As a general rule of thumb, the Greenhouse–Geisser correction is the preferred correction method when the epsilon estimate is below 0.75. Otherwise, the Huynh–Feldt correction is preferred.
How do you know if a Mauchly’s test is significant?
→ If Mauchly’s test statistic is significant (i.e. has a probability value less than . 05) we conclude that there are significant differences between the variance of differences: the condition of sphericity has not been met.
What does Mauchly’s test of sphericity tell you?
Mauchly’s Test of Sphericity indicated that the assumption of sphericity had not been violated, χ2(2) = 3.343, p = . If your data does not violate the assumption of sphericity, you do not need to modify your degrees of freedom. [If you are using SPSS, your results will be presented in the “sphericity assumed” row(s).]
What is Bartlett’s test of sphericity?
Bartlett’s test of sphericity tests the hypothesis that your correlation matrix is an identity matrix, which would indicate that your variables are unrelated and therefore unsuitable for structure detection.
What does it mean if sphericity is not violated?
[If you are using SPSS, your results will be presented in the “sphericity assumed” row(s).] Not violating this assumption means that the F-statistic that you have calculated is valid and can be used to determine statistical significance.
How does the greenhouse Geisser correction work?
The correction functions as both an estimate of epsilon (sphericity) and a correction for lack of sphericity. To correct for this inflation, multiply the Greenhouse–Geisser estimate of epsilon to the degrees of freedom used to calculate the F critical value.