Researchers have observed that rainforest areas next to clear-cuts (less than 100 meters away) have a reduced tree biomass compared to rainforest areas far from clear-cuts. To go further, Laurance et al. (1997) tested whether rainforest areas more distant from the clear-cuts were also affected. They compiled data on the biomass change after clear-cutting (in tons/hectare/year) for 36 rainforest areas between 100 m and several kilometers from clear-cuts. The data are as follows:

a. Describe the way(s) that this distribution differs from a normal distribution.

b. Test whether there is a change in biomass of rainforest areas following clear-cutting, using a test that does not assume a normal distribution.

Transcribed Image Text:

-10.8.-10.8, -4.9.-4.9, -2.6.-2.6, -1.6.-1.6, -3,-3, -6.2.-6.2, -6.5. -6.5, -9.2.-9.2, -3.6.-3.6,-1.8,-1.8, -1.0.-1.0, 0.2,0.2, 0.2,0.2, 0.1,0.1, -0.3,-0.3, -1.4.-1.4,-1.5.-1.5, -0.8,-0.8, 0.3,0.3, 0.6.0.6, 1.0,1.0, 1.2. 1.2, 2.9.2.9, 3.5,3.5, 4.3.4.3, 4.7.4.7, 2.9.2.9, 2.8,2.8, 2.5,2.5, 1.7,1.7, 2.7. 2.7, 1.2.1.2, 0.1.0.1, 1.3,1.3, 2.3,2.3, 0.5.0.5.