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By using the natural complex randomization method, the accuracy analysis is made of four kinds of statistical test schemes generally used in precipitation enhancement effectiveness evaluation, in which the “false effectiveness” is used to reflect the accuracy of evaluation to find out the different factors affecting the accuracy and to compare the accuracy of the different statistical schemes. It is found that the accuracy of the evaluation is relative to the quantityies of operation samples and historical samples. The accuracy increases with the increasing quantity of samples with the increment becoming gentle at last. Under the same condition, the historical regression method is more accurate than the others. Under the prescribed significance level, the historical regression method needs the least samples to reach the approximately same confidence level, while the double ratio analysis method and the comparative test need more samples, and the series experiment needs the most. The regression ratio method, a seldomly used statistical analysis method, is also discussed. The “false effectiveness” analysis concludes that the regression method is more accurate than the historical regression method.