There is exactly one outlier on the lower end.
There is at least one outlier on the lower end.
There is exactly one outlier on the higher end.
There is at least one outlier on the higher end.
There are no outliers.
An advantage of using only one variety of sea anemones is that there should be less variability in the response to each treatment.
A disadvantage of using only one variety of sea anemones is that the scope of inference is limited only to that type of anemone.
An advantage of using aquariums is that it is easier to maintain control to avoid confounding factors.
A disadvantage of using aquariums is that the anemones might respond differently in the ocean than they do in the aquariums.
If the anemones in the aquariums with increased acidity are less healthy than those without increased acidity, it cannot be determined that the increased acidity caused the response.