符号检验法（Sign test）
- 符号检验法对应于相关样本的t检验，根据两个相关样本的每一对数据之差的符号（正负）来进行检验。
- 符号检验法可用于顺序型与类目型的数据。
* The symbolic test method corresponds to the t test of the relevant samples, and is tested according to the sign (positive or negative) of the difference between each pair of data of the two relevant samples. * Symbolic testing can be used for sequential and categorical data.
检验步骤（checking procedure）
- 1.提出假设（H0：p（x>y）=0.5/差值d总体的中位数为0）；
- 2.根据H0所提供的前提条件确立统计模型
- 3.规定显著性水平α，随之确定否定域；
- 4.计算检验统计量的值；
- 5.做出决策。
*Hypothesis (H0: p (x>y) =0.5/ The median of the difference d population is 0); *2. Establish the statistical model according to the preconditions provided by H0 *3. Specify the significance level α, and then determine the negative domain; *4. Calculate the value of the test statistic; *5. Make decisions.
大样本情况下的符号检验法（Symbolic test method in case of large sample）
- 大样本（n>25）情况下，可以用与二项分布近似的正态分布进行符号检验。
* For large samples (n>25), the sign test can be performed with a normal distribution approximating the binomial distribution.