Mean, standard deviation, and SEM
Label the statistic, sample size, units, and error-bar meaning wherever the summary appears.
Mean describes center
The arithmetic mean is the sum divided by the observation count. It can be sensitive to outliers and may not represent a skewed distribution well.
Sample SD describes spread
Sample standard deviation commonly uses n − 1 when estimating population variability from a sample. It describes observations, not certainty in the mean.
SEM describes estimated mean precision
SEM is sample SD divided by the square root of n. It decreases as sample size grows and should not be relabeled as the spread of individual observations.
Keep labels consistent
State n and identify whether prose, tables, and error bars use SD, SEM, or confidence intervals. Matching numbers with inconsistent labels remain ambiguous.
Sources and boundaries
Solice develops LabCrux. The independent sources above do not sponsor or endorse the product. This page explains a review method; your experimental evidence, course instructions, and instructor remain authoritative.