Example Discrete variables which are difficult to change

Example Discrete variables which are difficult to change Assume that a reaction with the general formula 

The solvents must be rigorously dried prior to use. It is therfore more convenient to run the experiments in dry THF in one context, and then do the drying procedure for dioxane and run the dioxane experiments. 

It is not practical to change the apparatus randomly over the series of experiments. 

It is of course possible to compute aliases of confounded effects from each block and then separate the confoundings by comparing the different aliases to each other. It will be a good exercise for the reader to do this. As a hint, the aliases of confounded effects which can be computed from the first block is given by the generators. 

If this analysis is made for the remaining blocks, it possible to compute all main effects and all two-variable interaction effects from the aliases obtained for each block. 

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