This International Standard specifies experimental methods for the evaluation of quality variation of manganese and chromium ores, whether natural or processed, for the purpose of defining sampling procedure by the mass-basis systematic method and the two-stage method as specified in the relevant International Standards. It also specifies methods for checking the precision of sampling by the mass-basis systematic method and two-stage method. NOTE — The evaluation of quality variation for the sampling procedure by the time-basis systematic method shall be derived on the basis of the mass-basis systematic method.