From 979f791675f60ff606648aed729d2189660de1e9 Mon Sep 17 00:00:00 2001
From: Johan Ur Riise <johan@riise-data.no>
Date: Wed, 16 Sep 2009 16:27:20 +0300
Subject: [PATCH] fix median

---
 numbers.lisp | 2 +-
 tests.lisp   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/numbers.lisp b/numbers.lisp
index 7c6ef52..7252e2a 100644
--- a/numbers.lisp
+++ b/numbers.lisp
@@ -97,7 +97,7 @@ interpolation coefficient V."
          (middle (truncate length 2)))
     (if (oddp length)
         (aref vector middle)
-        (/ (+ (aref vector middle) (aref vector (1+ middle))) 2))))
+        (/ (+ (aref vector middle) (aref vector (1- middle))) 2))))
 
 (declaim (inline variance))
 (defun variance (sample &key (biased t))
diff --git a/tests.lisp b/tests.lisp
index 89bbf81..e76a7d3 100644
--- a/tests.lisp
+++ b/tests.lisp
@@ -855,7 +855,7 @@
 
 (deftest median.2
     (median '(100 0 99 1 98 2 97 96))
-  195/2)
+  193/2)
 
 (deftest variance.1
     (variance (list 1 2 3))
-- 
2.11.4.GIT