Refer to the EPA study of mercury poisoning in Maine lakes, Exercise 10.77. Lakes can be classified into three trophic states: Oligotrophic lakes have a balance between decaying vegetation and living organisms; eutrophic lakes have a high decay rate in the top layer of water; and, mesotrophic lakes have a moderate amount of nutrients in the water. One goal of the study was to compare the mercury level distributions for the three types of Maine lakes. Data on mercury level (parts per million) and type of 118 Maine lakes are saved in the MAINELAKE file.

a. For each lake type, determine if the mercury levels are approximately normally distributed.

b. Given the result, part a, explain why a nonparametric analysis is appropriate.

c. Conduct the Kruskal–Wallis test to compare the mercury level distributions for the three types of Maine lakes. Use α = .05.

Data from Exercise 10.77

Chemists at Kyushu University (Japan) examined the linear relationship between the maximum absorption rate y (in nanomoles) and the Hammett substituent constant x for meta cyclophane compounds (Journal of Organic Chemistry, July 1995). The data for variants of two compounds are given in the table. The variants of compound 1 are labeled 1a, 1b, 1d, 1e, 1f, 1g, and 1h; the variants of compound 2 are 2a, 2b, 2c, and 2d.

Transcribed Image Text:

ORGCHEM Maximum Hammett Compound Absorption y Constant x la 298 0.00 1b 346 .75 1d 303 .06 le 314 -26 1f 302 .18 1g 332 .42 1h 302 -.19 2a 343 .52 2b 367 1.01 2c 325 .37 2d 331 .53