Hard drugs, definition

Equally critical to a properly designed study is sample adequacy (i.e., size and appropriateness). It is hard to make definitive conclusions with very small sample sizes (e.g., five per group) because variation is too great. The minimal sample size needed to make inferences also depends on how large the experimental drug-placebo effect size is (i.e., the larger the effect size, the smaller the sample needed). 

Many makers, however, seek more or less successfully to still further increase the value of soap in this direction by the incorporation of various drugs and chemicals, and the number of medicated soaps on the market is now very large. Such soaps may consist of either hard or soft soaps to which certain medicaments have been added, and can be roughly divided into two classes, (a) those which contain a specific for various definite diseases, the intention being that the remedy should be absorbed by the pores of the skin and thus penetrate the system, and (b) those impregnated with chemicals intended to act as antiseptics or germicides, or, generally, as disinfectants. 

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