SDとSEMの使い分け

SD: standard deviation
SEM: standard error of means

SEM=SD/√nが成立。

こちらから抜粋

Although the SD and the SEM are related (SEM=SD/√n), they give two very different types of information. Whereas the SD estimates the variability in the study sample, the SEM estimates the precision and uncertainty of how the study sample represents the underlying population. In other words, the SD tells us the distribution of individual data points around the mean, and the SEM informs us how precise our estimate of the mean is. It is therefore inappropriate and incorrect to present data only as the mean (SEM).