Answer:
B: Yes, the participants are grouped by sun exposure, and then both treatments are randomly assigned within each group.
Step-by-step explanation:
Randomized block design is one in which the experimental units are categorized into groups which we call blocks. Thereafter, treatments will be randomly allocated to the experimental units inside each of the blocks.
Now, from the question, we can see that they were grouped in Blocks according to their outdoor activity which is degree of exposure to the sun. Thereafter the individual groups are randomly assigned treatments.
Thus, Option B is correct.
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