P2.7 A student who was having difficulty with measured-unit-accuracy cell boundaries showed five lists to the instructor and asked which one was correct. Observed values are in integers. Cell 1 2 3 4 5 1 2 3 4 5 10-20 20-30 30-40 40-50 50-60 9.5-19.5 19.5-29.5 29.5-39.5 39.5-49.5 49.5-59.5 10-20 20-35 35-40 40-50 50-60 > 10-20 20-30 30-40 240-