Calculadora de Erro Padrão (da média)

The Standard Error of the Mean Calculator estimates the precision of a sample mean relative to the population mean. The standard error (SE) is calculated by dividing the sample standard deviation (s) by the square root of the sample size (n). A smaller SE indicates a more reliable sample mean as an estimate of the population mean. This tool is essential in scientific research, data analysis, and statistical inference.

To use the calculator, enter your sample standard deviation and sample size. The result is the standard error, which indicates the expected variability of the sample mean. For example, in a study with s = 10 and n = 100, the SE will be 1.0, suggesting the sample mean is about 1 unit away from the population mean. This helps in constructing confidence intervals and conducting hypothesis tests.

The standard error is widely used in fields like psychology, medicine, economics, and engineering. It allows assessing the margin of error in opinion polls, clinical trials, and experiments. Caution: SE assumes a random and independent sample. Non-random or biased samples can invalidate the interpretation. Additionally, SE is sensitive to outliers, which inflate the standard deviation.

Remember that standard error is not the same as standard deviation. While standard deviation measures the spread of individual data points, SE measures the precision of the sample mean. For small samples (n < 30), consider using the t-distribution for more accurate confidence intervals. This calculator is a quick tool for researchers and students needing reliable estimates.