Question

question 4 (1 point) the makers of stop stank mouthwash want to prove that their mouthwash kills more bacteria than the other 4 leading brands of mouthwash. researchers organize 50 individuals into 5 groups of 10 test subjects. each subject has their mouth swabbed for bacteria and breath scored by a panel of scientists and then they are assigned a brand of mouthwash to use for a month. every friday, the scientists swab each individuals mouth for bacteria and again scores their breath. after a month, the scientists data is compiled and studied. identify three controlled variable(s) in this experiment. (choose all that apply) a) stop stank mouthwash b) the panel of judges c) the swabs d) the breath score e) the size of the groups f) the amount of bacteria

Explanation:

In an experiment, controlled variables are factors that are kept the same to ensure that only the variable of interest (the type of mouth - wash) affects the outcome. The panel of judges, the swabs (used for collecting samples), and the breath score (measurement of breath quality) are factors that need to be consistent across all groups to accurately test the effectiveness of the mouth - wash. The size of the groups is a variable related to experimental design but not a factor that directly impacts the comparison of mouth - wash effectiveness in the same way as the others. The amount of bacteria is the dependent variable being measured.

Answer:

b. The panel of judges
c. The swabs
d. The breath score