Arsenic in groundwater. Enviromental Science and Technology (January 2005) reported on a study of the reliability of a chemical kit to test for arsenic in groundwater. The field kit was used to test a sample of 328 groundwater wellsin Bangladesh. In addition to the arsenic level (micrograms per liter), the latitude (degrees), longitude (degrees), and depth (feet) of each well was measured. The first and last 5 observations are listed below.

WELLID LATITUDE LONGITUDE DEPTH ARSENIC