JIS Z 9048:1979

This Japanese Industrial Standard specifies the significance test method to determine whether it can be said that one population mean differs from (is either larger or smaller than) the other on the basis of the measured values obtained from each population (or from the lot to be considered to be good representative of the population) when the standard deviations of the two populations are unknown. (Standard deviations unknown of populations, one sided). The text of this standard gives the significance test method to be applied only when a pair of sample is equal in size and, at the same time, standard deviations are considered to be the same. If otherwise, refer to Reference appended to the end of this standard.

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