Fixed degrees of freed in t-stat for intercept

diff --git a/src/language/stats/regression.q b/src/language/stats/regression.q
index 8f9979ae73306476c8eec5a6c42105a01a951d7a..53ac594b455ff4955959b3b8dcf2049ec98915b9 100644 (file)
--- a/src/language/stats/regression.q
+++ b/src/language/stats/regression.q
@@ -206,7 +206,7 @@ reg_stats_coeff (linreg * c, void *aux_)
   tab_double (t, 4, 1, 0, 0.0, NULL);
   t_stat = linreg_intercept (c) / std_err;
   tab_double (t, 5, 1, 0, t_stat, NULL);
-  pval = 2 * gsl_cdf_tdist_Q (fabs (t_stat), 1.0);
+  pval = 2 * gsl_cdf_tdist_Q (fabs (t_stat), (double) (linreg_n_obs (c) - linreg_n_coeffs (c)));
   tab_double (t, 6, 1, 0, pval, NULL);
   for (j = 0; j < linreg_n_coeffs (c); j++)
     {

diff --git a/tests/language/stats/regression.at b/tests/language/stats/regression.at
index 11ce07fa7aa672f6a8cc6137084313d5f6749cd8..0ea3efc8a256aabf1bbe963e38d1d80cfa818d70 100644 (file)
--- a/tests/language/stats/regression.at
+++ b/tests/language/stats/regression.at
@@ -38,7 +38,7 @@ Table: ANOVA
 
 Table: Coefficients
 ,,B,Std. Error,Beta,t,Significance
-,(Constant),2.19,2.36,.00,.93,.52
+,(Constant),2.19,2.36,.00,.93,.38
 ,v0,1.81,1.05,.17,1.72,.12
 ,v1,-3.43,.33,-1.03,-10.33,.00
 ,,,,,,
@@ -1585,7 +1585,7 @@ Table: ANOVA
 
 Table: Coefficients
 ,,B,Std. Error,Beta,t,Significance
-,(Constant),1.24,.42,.00,2.95,.21
+,(Constant),1.24,.42,.00,2.95,.00
 ,v1,1.37,.72,.05,1.89,.06
 ,,,,,,
 ])