What does the standard error measure primarily assess?

The standard error primarily assesses how values differ from the mean, providing insight into the variability and dispersion of sample means around the population mean. It is a statistical measure that indicates the extent to which the sample mean is expected to fluctuate from the true population mean.

In practical terms, a smaller standard error suggests that the sample mean is likely to be a more accurate reflection of the population mean, while a larger standard error indicates more variability and uncertainty. Understanding the standard error is crucial for making inferences about a population based on sample data, as it helps in determining the reliability of statistical estimates and the significance of test results.