Traces of toxic, man-made hexachlorohexanes in North Sea sediments were extracted by a known process and by a new procedure, and measured by chromatography. Is the mean concentration found by procedure A significantly different from that of the conventional procedure?
Method Concentration Found (pg/g) Standard Dev.(pg/g) Number of replications
Conventional 34.4 3.6 6
Procedure A 42.9 1.2 6