Parrots can develop cognitive issues as they get older. This may compromise their memory, ability to learn,
awareness, sight, and hearing. A researcher wishes to conduct a study to find which of two medicines,
Medicine A or Medicine B, is more effective in improving cognitive health. A total of 150 parrots that are at
least 12 years old will be randomly selected from sanctuaries around the United States. The researcher will
get consent from all owners, treat the parrots for 1 year, and evaluate changes in cognitive health.
Part A: How would the study benefit from adding a control group? (2 points)
Part B: What is the best way to randomly place the parrots into the Medicine A, Medicine B, and control
groups? (4 points)
Part C: The researcher wants to use a blocking variable to place the parrots into groups instead of doing it randomly. He decides to block either by breed or sanctuary. Explain which would be the best blocking
method. (4 points)

This would aid throughout the comparison, since it could be used to examine the consequences of the medicines on some kind of collection of parrots, as well as the lack of either treatment.

Part B:

"Random sampling" would be the best way to randomly place the parrots.

Part C:

The best blocking method would be "Breed".

Therefore we know that a blocking variable should be consistent and unchangeable.
The parrots in some kind of a sanctuary might fluctuate in breed as well as quantity, and certain other considerations like as upkeep by the government may have an impact somewhere on parrots' circumstances.

Thus the response above is correct.

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