Tests of the Hypothesis That a Linear Regression System Obeys Two Separate Regimes

Several approaches are explored for testing the hypothesis that no switch has occurred in the true values of the parameters of a linear regression system. The distribution of the relevant likelihood ratio λ is analyzed on the basis of the empirical distribution resulting from some sampling experiments. The hypothesis that −2 log λ has the χ2 distribution with the appropriate degrees of freedom is rejected and an empirical table of percentage points is obtained. Finally some small sample tests are suggested.