Refer to the Environmental Science & Technology (Jan. 2005) study of the reliability of a commercial kit to test for arsenic in groundwater, Exercise 11.24. Recall that you fit a first-order model for arsenic level (y) as a function of latitude, longitude, and depth to the data saved in the ASWELLS file. Conduct a complete residual analysis of the model. Do you recommend any model modifications?    

Data from Exercise 11.24

Refer to the Environmental Science & Technology (Jan. 2005) study of the reliability of a commercial kit to test for arsenic in groundwater, Exercise 7.59. Recall that a field kit was used to test a sample of 328 groundwater wells in Bangladesh. In addition to the arsenic level (micrograms per liter), the latitude (degrees), longitude (degrees), and depth (feet) of each well was measured. The data are saved in the ASWELLS file.

Transcribed Image Text:

Tally for Discrete Variables: KIT-COLOR KIT-COLOR Count Percent Green 178 54.27 Red 150 45.73 N= 328