Forest fragmentation study. Refer to the Conservation Ecology (Dec. 2003) study on the causes of fragmentation in 54 South American forests, presented in Exercise 2.166

(p. 125). Recall that the cause is classified as either anthropogenic or natural in origin. The anthropogenic fragmentation index (saved in the FRAG file) for the South American forests has an approximate exponential distribution with a mean of 23.

a. Find the probability that a South American forest has an anthropogenic fragmentation index between 20 and 40.

b. Find the probability that a South American forest has an anthropogenic fragmentation index below 50.

c. The natural fragmentation index (also saved in the FRAG file) does not have an approximate exponential distribution. Why?