--- original_random.py	2010-12-28 17:35:14.391227658 +0100
+++ random.py	2010-12-28 17:42:15.027819418 +0100
@@ -489,7 +489,16 @@
         """Gamma distribution.  Not the gamma function!
 
         Conditions on the parameters are alpha > 0 and beta > 0.
-
+        
+        Mean is alpha*beta
+        Variance is alpha * ( beta ** 2 )
+        The exact formula for this distribution is 
+        def f ( x , alpha , beta ) :
+            return ( 
+            ( ( x ** ( alpha - 1 ) ) * math.exp( - x / beta ) ) 
+            / 
+            ( math.gamma( alpha ) * ( beta ** alpha ) )
+            )
         """
 
         # alpha > 0, beta > 0, mean is alpha*beta, variance is alpha*beta**2