GLM: Do not print the intercept if the model is unbalanced

[pspp] / src / language / stats / glm.c

diff --git a/src/language/stats/glm.c b/src/language/stats/glm.c
index e4b3c17b21bb66ec4f46a30a52114668059cd90b..a5e047e86d1dcb118a5785b126a30411e52ea695 100644 (file)
--- a/src/language/stats/glm.c
+++ b/src/language/stats/glm.c
@@ -775,12 +775,17 @@ output_glm (const struct glm_spec *cmd, const struct glm_workspace *ws)
       const double df = 1.0;
       const double F = intercept_ssq / df / mse;
       tab_text (t, 0, r, TAB_LEFT | TAT_TITLE, _("Intercept"));
-      tab_double (t, 1, r, 0, intercept_ssq, NULL, RC_OTHER);
-      tab_double (t, 2, r, 0, 1.00, NULL, RC_WEIGHT);
-      tab_double (t, 3, r, 0, intercept_ssq / df, NULL, RC_OTHER);
-      tab_double (t, 4, r, 0, F, NULL, RC_OTHER);
-      tab_double (t, 5, r, 0, gsl_cdf_fdist_Q (F, df, n_total - df_corr),
-                 NULL, RC_PVALUE);
+      /* The intercept for unbalanced models is of limited use and
+        nobody knows how to calculate it properly */
+      if (categoricals_isbalanced (ws->cats))
+       {
+         tab_double (t, 1, r, 0, intercept_ssq, NULL, RC_OTHER);
+         tab_double (t, 2, r, 0, 1.00, NULL, RC_WEIGHT);
+         tab_double (t, 3, r, 0, intercept_ssq / df, NULL, RC_OTHER);
+         tab_double (t, 4, r, 0, F, NULL, RC_OTHER);
+         tab_double (t, 5, r, 0, gsl_cdf_fdist_Q (F, df, n_total - df_corr),
+                     NULL, RC_PVALUE);
+       }
       r++;
     }