科学论文里经常出现的Means and s.e.m是什么意思

mean±SD或 mean±SEM平均数±标准差或标准误

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）……

mean to do和mean doing的区别如下：

一。means doing

mean当做意思意味讲时，是及物动词，refusingto have anything to do with something or somebody这个动名词短语做mean的宾语。

二。mean to do一般理解为打算做某事

联合抵制这个词的意思是拒绝用某物来对付一些事或者一些人~

mean to do和mean doing的具体意思如下：

⑴mean to do

英 [mi:n tu: du:] 美 [min tu du]

词典意思为：

打算做；有意做

网络意思为：

打算； 打算做某事； 打算/想做某事

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