When repeated measures are used which assumption is violated?

assumption of sphericity
Unfortunately, repeated measures ANOVAs are particularly susceptible to violating the assumption of sphericity, which causes the test to become too liberal (i.e., leads to an increase in the Type I error rate; that is, the likelihood of detecting a statistically significant result when there isn’t one).

Does repeated measures Anova assume normality?

The assumption of normality of difference scores is a statistical assumption that needs to be tested for when comparing three or more observations of a continuous outcome with repeated-measures ANOVA. Repeated-measures ANOVA should not be conducted when the assumption of normality of difference scores is violated.

Which test is suitable for repeated measures when test of assumption are violated?

The standard univariate ANOVA F test is not recommended when the within- subjects factor has more then two levels because on of its assumptions, the sphericity assumption is commonly violated, and the ANOVA F test yields inaccurate p values to the extent that this assumption is violated.

What are the assumptions for one-way ANOVA?

What are the assumptions of a One-Way ANOVA?

• Normality – That each sample is taken from a normally distributed population.
• Sample independence – that each sample has been drawn independently of the other samples.
• Variance Equality – That the variance of data in the different groups should be the same.

What does one way repeated measures ANOVA stand for?

The One-Way Repeated Measures ANOVA is also sometimes called the Repeated Measures ANOVA, One-Way Repeated Measures ANOVA F Test, Repeated Measures ANOVA F Test, Within-Subjects ANOVA, ANOVA for Correlated Samples, Repeated Measures Analysis of Variance. Every statistical method has assumptions.

How is sphericity tested in repeated measures ANOVA?

Repeated Measures ANOVA – Assumptions. Sphericity: the variances of all difference scores among the test variables must be equal in the population. Sphericity is sometimes tested with Mauchly’s test. If sphericity is rejected, results may be corrected with the Huynh-Feldt or Greenhouse-Geisser correction.

How to detect outliers in repeated measures ANOVA?

Fortunately, when using SPSS Statistics to run a repeated measures ANOVA on your data, you can easily detect possible outliers. In our enhanced repeated measures ANOVA guide, we: (a) show you how to detect outliers using SPSS Statistics; and (b) discuss some of the options you have in order to deal with outliers.

Can a post hoc test be used in repeated measures ANOVA?

Post hoc tests for within-subjects factors (adtype in our case) are well hidden behind the O ptions rather than the P ost Hoc button. The latter only allows post hoc tests for between-subjects effects, which we no longer have. *Repeated measures ANOVA for adtype only with post-hoc tests for within-subjects effect.