Standard Deviation of Errors
Statistics • Multiple Regression
Frequently Asked Questions
What is the standard deviation of errors (s_e) in multiple regression?
s_e is the standard error of estimate and summarizes the typical size of residuals in the units of the response variable y. Smaller s_e generally indicates predictions are closer to observed values, holding the model form and predictors fixed.
How is s_e computed from SSE and degrees of freedom?
The calculator uses the residual sum of squares (SSE) and the residual degrees of freedom to compute s_e = sqrt(SSE / df). The df depends on the sample size and the number of estimated parameters (including the intercept if selected).
Why are some rows removed before the calculation runs?
Rows with missing or non-numeric values in the selected response or predictor columns are dropped so the regression and residuals are computed on valid numeric data. This prevents errors and keeps SSE and s_e consistent with the chosen variables.
What does "Compare s_e across model sizes" do?
It builds a sequence of models by adding predictors in the current checklist order and computes s_e at each step. This helps you see how the typical error changes as more predictors are included.
How should I interpret the residual histogram and bands at plus/minus s_e and plus/minus 2 s_e?
The histogram shows the distribution of residuals with a normal overlay, while the guides at plus/minus s_e and plus/minus 2 s_e provide practical error-size reference points. The strip plot groups observations into bands such as |e| < s_e, |e| < 2 s_e, and |e| >= 2 s_e to highlight small versus large errors.