2. Control methods for excluding irrelevant variables and control variables.
Control method:
Using the control of the subjects themselves-the internal design of the subjects; Pairing subjects-making each group equal; Keep the variables unchanged-the same age, the same physical environment; Random distribution-if n is large enough, it is statistically considered to be the same; Draw lots, random numbers, use the original order and other methods; Incorporate variables into the experimental design-become a multi-factor experimental design; Use * * * variable analysis. 3. Minimize the error variance.
1) Source:
Individual differences; Measurement error. 2) Practice:
Properly control the experimental situation; And the measurement reliability is improved.