fixed p-value computation in test of coefficients

diff --git a/src/language/stats/ChangeLog b/src/language/stats/ChangeLog
index 712c8428332688cbdcd47ed64f90b8c708f8ed02..ef085bf7d832aa41605774218be3cfdbe6da1879 100644 (file)
--- a/src/language/stats/ChangeLog
+++ b/src/language/stats/ChangeLog
@@ -1,3 +1,8 @@
+2007-02-04  Jason Stover  <jhs@math.gcsu.edu>
+
+       * regression.q: Fixed p-value computation in the test for
+       individual regression coefficients.
+
 Mon Jan 15 11:03:20 2007  Ben Pfaff  <blp@gnu.org>
 
        Fix bugs found by valgrind when --enable-debug is used with the

diff --git a/src/language/stats/regression.q b/src/language/stats/regression.q
index a5851ff34e4857b2ee086ee8a630ffb9de7091c9..287847a855452d3fba03ce7f1f6cb22405556c6d 100644 (file)
--- a/src/language/stats/regression.q
+++ b/src/language/stats/regression.q
@@ -269,7 +269,7 @@ reg_stats_coeff (pspp_linreg_cache * c)
       /*
          P values for the test statistic above.
        */
-      pval = 2 * gsl_cdf_tdist_Q (fabs (t_stat), 1.0);
+      pval = 2 * gsl_cdf_tdist_Q (fabs (t_stat), (double) (c->n_obs - c->n_coeffs));
       tab_float (t, 6, j + 1, 0, pval, 10, 2);
     }
   tab_title (t, _("Coefficients"));