An R chart, analysis of means charts, and the range square ratio test, are applied to spectrographic data to compare two internal standards and two different buffer salts in the analysis of solutions of organic ash. The range square ratio test confirms the indications derived from the graphical methods that cobalt is a better standard for manganese, molybdenum is better for lead, and that sodium silicate is superior to lithium chloride as a buffer salt.
Barbara T. Keeler, "The Application of Statistical Methods to a Problem In Spectrochemical Analysis," Appl. Spectrosc. 15, 170-173 (1961)