A hand sanitizer was advertised to be more effective at killing bacteria than any antibacterial soap. Students were split evenly into 4 groups test this claim. Groups 1-3 washed their hands using the assigned hand sanitizer or soap (see
table) and warm water for two minutes, and then dried their hands with a paper towel. Group 4 rubbed their hands
vigorously for 2 minutes in warm water, without any soap or sanitizer, and then dried their hands with a paper towel.
After washing, each student’s hands were swabbed and the swab was applied to a culture plate and incubated. Finally,
the bacterial cultures were counted.

Treatment Bacteria Growth (# of bacteria)
Group 1: Hand sanitizer 28
Group 2: Soap A 12
Group 3: Soap B 13
Group 4: Warm water 24
A. What are the independent and dependent variables in this experiment?
B. Based on the claims of the hand sanitizer advertisement, what was the hypothesis for this experiment?
C. What is the control group?
D. What are 3 constants?
E. Based on the results in the data table, was the advertisement supported or refuted/rejected? Explain your answer.