Ms. Rwants to find out which bug spray works best: Off, Avon, or
Cutter, Four students help her. These are her results:
Group 1 (OFF): 4 mosquito bites
Group 2 (Avon): 18 mosquito bites
Group 3 (Cutter): 10 mosquito bites
Group 4 (none): 28 mosquito bites
what should have been kept constant
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