t

1 files changed, 14 insertions, 4 deletions

diff --git a/ministat.c b/ministat.c
index f8c4414..076186d 100644
--- a/ministat.c
+++ b/ministat.c
@@ -379,10 +379,20 @@ Relative(struct dataset *ds, struct dataset *rs, int confidx)
 	double p = 100 *(1 - pvalue(welch(ds, rs), dof(ds, rs)));
 
 	if (p > studentpct[confidx]) {
-		printf("Difference at %.1f%% confidence: %g (%.2f%%)\n",
-		       p,
-		       Avg(ds) - Avg(rs),
-		       (Avg(ds) - Avg(rs)) / Avg(ds) * 100);
+		double c, d;
+		int v;
+
+		d = Avg(ds) - Avg(rs);
+
+		v = dof(ds, rs);
+		if (v > NSTUDENT)
+			c = student[0][confidx];
+		else
+			c = student[v][confidx];
+		c *= sqrt(Var(ds)/ds->n - Var(rs)/rs->n);
+
+		printf("Difference at %.1f%% confidence: %g +- %g (%.2f%% +- %.3f%%)\n", p,
+		       d, c, d / Avg(ds) * 100, c / Avg(ds) * 1000);
 	}
 }