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  3. Experimental Design in R

Exercise

Drawing BIBDs with agricolae

We can also use agricolae to draw BIBDs. design.bib() takes, at minimum, the treatments (treats), an integer k corresponding to the number of levels of the blocks, and a seed as inputs.

The main thing you should notice about a BIBD is that not every treatment will be used in each block (column) of the output.

From the video and the last exercise, however, you know that sometimes a BIBD isn't valid and that you have to do a little math to be sure your BIBD design is possible. design.bib() will return an error message letting you know if a design is not valid.

Let's draw a few BIBDs with agricolae so we can see the different warning messages and errors the package provides.

Instructions 1/3

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  • Create my_design_bibd_1 using A, B, and C for the treatments, 4 blocks, and a seed of 42.