standard error of measurement
The standard deviation (SD) represents variation in the values of a variable, whereas the standard error of the mean (SEM) represents the spread that the mean of a sample of the values would have if you kept taking samples. So the SEM gives you an idea of the accuracy of the mean, and the SD gives you an idea of the variability of single observations. The two are related: SEM = SD/(square root of sample size).
简单地说就是平均数的抽样误差,反映平均数的抽样准确性,国内用标准偏移值SD的较多,SEM=SD除以(样本数的平方根)……
sem高级认证一般说的是百度认证,分为初级,中级和高级,初级是50道选择题,中级是两次考试,也都是选择题,高级是需要答辩,百度认证对于百度代理商来说,是有数量要求的,这是百度对代理商评级的一个标准,其实就是服务客户的一个由头,高级认证算是营销领域的专家级别,百度一年也出不了10个认证吧,初级和中级背题就可以过,在甲方从事sem没有这个要求,在乙方,有证书会有相应的挂靠补助和加点工资,算是百度对你考试的补偿了欢迎分享,转载请注明来源:夏雨云
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