Much of the Arctic soil is frozen year-round. Scientists measured soil thaw depth in areas
burned in the Arctic at 5-meter intervals. Additionally, the thickness of surface organic layer
was measured at each site. The data is collected in the table below.
Treatment group
Average thaw depth (cm)
Average surface organic thickness
(cm)
Unburned
plots
41
32
46 years since last
fire
42.5
31.5
32 years since last
fire
47
35.5
12 years since last
fire
52
37


Identify one modification that could be made to the investigation would be to measure the surface organic material in different seasons ?