15.72 Refer to Exercise 15.71. The data in this table are the cadmium concentrations found in aphids that fed on the plants grown in soil amended with sludge.

a. Use the MINITAB normal probability plot of the residuals and the plot of residuals versus rates of application to assess whether the assumptions of normality and constant variance are reasonable in this case.

b. Based on your conclusions in part

a, use an appropriate statistical method to test for significant differences in cadmium concentrations for the six rates of application.

Transcribed Image Text:

Harvest Rate 1 2 3 Control 16.2 55.8 65.8 1234 16.9 119.4 181.1 2 12.7 171.9 184.6 3 31.3 128.4 196.4 38.5 182.0 163.7 5 20.6 191.3 242.8