I conducted an experiment with a latin square design.
How do I arrange the data in IBM SPSS to analyze it in one file? I've watched this video https://www.youtube.com/watch?v=APvlPjYSSaI, where groups (e.g., Block 1 = Group 1, Block 2 = Group 2, Block 3 = Group 3) have been built in addition to the time period of measurement. But in the example of the video, the order of the treatments are the same (and not arranged in a latin square as in my example). So how should I arrange the data from the latin square design in SPSS?
This is a within subject design, as I measure after each treatment my dependent variable (3 times measurement of dependent variable per subject). Each Block contains 5 subjects.
latin squares
Latin squares are usually used to balance the possible treatments in an experiment, and to prevent confounding the results with the order of treatment. There is no special way to analyze the latin square. You just make a note of it when describing your methods.
arranging data for analysis
From your description, this is a between within design. Each subject was measured 3 times, and subjects are grouped by the order of treatments. Your data should be arranged like so for ANOVA:
I believe this thread would be useful for you: https://stats.stackexchange.com/questions/244636/evaluating-contrasts-in-repeated-measures-anova-spss