1 files changed, 42 insertions, 0 deletions
diff --git a/gsl-1.9/statistics/ttest_source.c b/gsl-1.9/statistics/ttest_source.c
new file mode 100644
index 0000000..f1ccc0b
--- /dev/null
+++ b/gsl-1.9/statistics/ttest_source.c
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+/* statistics/ttest_source.c
+ * 
+ * Copyright (C) 1996, 1997, 1998, 1999, 2000 Jim Davies, Brian Gough
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+double 
+FUNCTION(gsl_stats,ttest) (const BASE data1[], 
+                           const size_t stride1, const size_t n1, 
+                           const BASE data2[],
+                           const size_t stride2, const size_t n2)
+{
+  /* runs a t-test between two datasets representing independent
+     samples. Tests to see if the difference between means of the
+     samples is different from zero */
+
+  /* find means for the two samples */
+  const double mean1 = FUNCTION(gsl_stats,mean) (data1, stride1, n1);
+  const double mean2 = FUNCTION(gsl_stats,mean) (data2, stride2, n2);
+
+  /* find pooled variance for the two samples */
+  const double pv = FUNCTION(gsl_stats,pvariance) (data1, stride1, n1, data2, stride2, n2);
+
+  /* calculate the t statistic */
+  const double t = (mean1 - mean2) / (sqrt (pv * ((1.0 / n1) + (1.0 / n2))));
+
+  return t;
+}
+