Latin Squares design

As you hopefully realized in the previous exercise, completely counterbalancing is not always a practical solution for taking into account order effects. This is because the number of different orders required gets really large as the number of possible conditions increases.

The most common workaround to this problem is the Latin Squares design, in which you do not completely counterbalance, but instead put each condition at every position (at least) once.

Which of the following examples has been constructed according to the Latin Squares design?