REPEATED MEASURE

WHAT IS REPEATED MEASURE?

The same entities take part in all conditions of an experiment

Variable

§One independent variable (categorical) 

(e.g. Time 1/ Time 2/ Time 3)

§One dependent variable (continous) 

(e.g. scores on the Confidence  in Coping with Statistics Test).

STEP BY STEP REPEATED MEASURE

#1.   Your dependent variable should be measured at the continuous   level   (i.e., they are interval or ratio variables).

#2.  Your independent variable should consist of at least two   categorical, "related groups" or "matched pairs". "Related groups"   indicates that the same subjects are present in both groups

#3.  There should be no significant outliers in the related groups. The   problem with outliers is that they can have a negative effect on   the   repeated measures ANOVA, distorting the differences   between the   related groups, and can reduce the accuracy of your results.

#4.   The distribution of the dependent variable in the two or more related   groups should be approximately normally distributed. You can test for   normality using the Shapiro-Wilk test of normality.

#5.   Known as sphericity, the variances of the differences between all   combinations of related groups must be equal. Unfortunately, repeated   measures ANOVAs are particularly susceptible to violating the   assumption of sphericity, which causes the test to become too liberal.

HOW TO REPORTING RESULT OF REPEATED MEASURE?

§A one-way repeated measures ANOVA was conducted to compare scores on the Confidence in Coping with Statistics test at Time 1 (prior to the intervention), Time 2 (following the intervention) and Time 3 (three-month follow-up) . The means and standard deviations are presented in Table XX. There was a significant effect for time [Wilks’ Lambda=.25, F(2, 28)=41.17, p<.0005, multivariate partial eta squared=.75.]