比较均值分析思路

sql： 

    def SubDependentDataSql(self, DatabaseName, TableName, DependentVariable, IndependentVariable):
        """
        DependentVariable 因变量
        IndependentVariable 自变量
        得到因变量的数据子数据：
            {
                N
                均值，
                标准差等
            }
        """
        subdependentdatasql = """
            select * from (
                select  
                    repDB.`{}` as `{}` 
                    ,COUNT(1) as N
                    ,SUM(convert(Ifnull(repDB.`{}`, 0),decimal(65,30))) as SUM
                    ,STDDEV_SAMP(convert(Ifnull(repDB.`{}`, 0),decimal(65,30))) as STD
                    ,MAX(convert(Ifnull(repDB.`{}`, 0),decimal(65,30))) as MAX 
                    ,MIN(convert(Ifnull(repDB.`{}`, 0),decimal(65,30))) as MIN 
                    ,AVG(convert(Ifnull(repDB.`{}`, 0),decimal(65,30))) as AVG 
                 from 
                {}.{} as  repDB 
                where 
                trim(Ifnull(repDB.`{}`, '')) <> '' 
                AND trim(Ifnull(repDB.`{}`, '')) <> ''
                group by repDB.`{}`
                ) as SUB
            order by CONVERT(SUB.`{}` , SIGNED)         
        """.format(
            DependentVariable,
            DependentVariable,
            IndependentVariable,
            IndependentVariable,
            IndependentVariable,
            IndependentVariable,
            IndependentVariable,
            DatabaseName,
            TableName,
            IndependentVariable,
            DependentVariable,
            DependentVariable,
            DependentVariable)

求中值前先查数据sql：

     def MedianValueDataSql(self, DatabaseName, TableName, DependentVariable, IndependentVariable, optionID):
        """
            求中值sql， 因变量有几个optionid， 就需要循环这条sql几遍
        :return:
        """
        medianvaluedatasql = """
            select 
                Ifnull(repDB.`{}`, 0) as `{}`                        
            from 
                {}.{} as  repDB 
            where 
                trim(Ifnull(repDB.`{}`, '')) <> '' 
                AND trim(Ifnull(repDB.`{}`, '')) = {}
            ORDER BY `{}`;
        """.format(IndependentVariable,
                   IndependentVariable,
                   DatabaseName,
                   TableName,
                   IndependentVariable,
                   DependentVariable,
                   optionID,
                   IndependentVariable
                   )

标准误平均值

　　　　标准误是样本均值与总体均值的误差估计

　　　　标准误=标准差/sqrt（样本量） （标准差就是样本算出来的标准差）