Runs Test for Residual Randomness
do_runs_test.RdPerforms a nonparametric runs test to evaluate whether a sequence of residuals is randomly distributed around a reference mean. The function also computes three-sigma control limits used to identify potential residual outliers.
Arguments
- x
Numeric vector of residuals.
- type
Character string specifying the assumed mean of the residuals. If
"resid"(default), the residual mean is assumed to be zero. Otherwise, the empirical mean ofxis used.- mixing
Character string specifying the alternative hypothesis for the runs test:
"two.sided": tests for both positive and negative autocorrelation (default)."less": left-tailed test detecting positive autocorrelation.
Value
A list containing:
sig3lim: Numeric vector of length two giving the lower and upper three-sigma control limits for the residuals.p.runs: P-value from the runs test for randomness.
A small p-value (e.g., < 0.05) indicates evidence that the residual
sequence is not random and may exhibit autocorrelation or other systematic
patterns.
Details
The runs test evaluates whether residuals exhibit non-random structure (e.g., positive or negative autocorrelation).