What is the difference between standard deviation and standard error

The standard deviation (SD) is a measure of the variability of a random variable. A standard error (SEM) is a measure of how precise an estimate is.

Step-by-step explanation:

The standard deviation (SD) is a measure of the variability of a random variable. A standard error (SEM) is a measure of how precise an estimate is.

The contrast between these two terms reflects the important distinction between data description and inference.

The SEM is always smaller than the SD.

Step-by-step explanation:

The standard deviation (SD) can be defined as a entity that measures the amount of dispersion for a set of data from the mean, while the standard error of the mean (SEM) measures the magnitude of deviation of the sample mean of the data from the true population mean.