Standard deviation and standard error of the mean
#MMPMID26045923
Lee DK
; In J
; Lee S
Korean J Anesthesiol
2015[Jun]; 68
(3
): 220-3
PMID26045923
show ga
In most clinical and experimental studies, the standard deviation (SD) and the
estimated standard error of the mean (SEM) are used to present the
characteristics of sample data and to explain statistical analysis results.
However, some authors occasionally muddle the distinctive usage between the SD
and SEM in medical literature. Because the process of calculating the SD and SEM
includes different statistical inferences, each of them has its own meaning. SD
is the dispersion of data in a normal distribution. In other words, SD indicates
how accurately the mean represents sample data. However the meaning of SEM
includes statistical inference based on the sampling distribution. SEM is the SD
of the theoretical distribution of the sample means (the sampling distribution).
While either SD or SEM can be applied to describe data and statistical results,
one should be aware of reasonable methods with which to use SD and SEM. We aim to
elucidate the distinctions between SD and SEM and to provide proper usage
guidelines for both, which summarize data and describe statistical results.
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