diff --git a/Changelog.md b/Changelog.md
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,3 +1,7 @@
+# Changes in 1.1.2
+
+- `Unbox` instances for `MeanNaive`, `WMeanNaive`, `WMeanKBN`.
+
 # Changes in 1.1.1
 
 - `Unbox` instance for `BinomAcc` is added.
diff --git a/Data/Monoid/Statistics/Numeric.hs b/Data/Monoid/Statistics/Numeric.hs
--- a/Data/Monoid/Statistics/Numeric.hs
+++ b/Data/Monoid/Statistics/Numeric.hs
@@ -450,15 +450,30 @@
   [| calcCountN |]
   [| CountG     |]
 
+derivingUnbox "MeanNaive"
+  [t| MeanNaive -> (Int,Double) |]
+  [| \(MeanNaive a b) -> (a,b)  |]
+  [| \(a,b) -> MeanNaive a b    |]
+
 derivingUnbox "MeanKBN"
-  [t| MeanKBN -> (Int,Double,Double) |]
-  [| \(MeanKBN a (KBNSum b c)) -> (a,b,c)   |]
-  [| \(a,b,c) -> MeanKBN a (KBNSum b c) |]
+  [t| MeanKBN -> (Int,Double,Double)      |]
+  [| \(MeanKBN a (KBNSum b c)) -> (a,b,c) |]
+  [| \(a,b,c) -> MeanKBN a (KBNSum b c)   |]
 
+derivingUnbox "WMeanNaive"
+  [t| WMeanNaive -> (Double,Double) |]
+  [| \(WMeanNaive a b) -> (a,b)     |]
+  [| \(a,b) -> WMeanNaive a b       |]
+
+derivingUnbox "WMeanKBN"
+  [t| WMeanKBN -> (Double,Double,Double,Double)         |]
+  [| \(WMeanKBN (KBNSum a b) (KBNSum c d)) -> (a,b,c,d) |]
+  [| \(a,b,c,d) -> WMeanKBN (KBNSum a b) (KBNSum c d)   |]
+
 derivingUnbox "Variance"
   [t| Variance -> (Int,Double,Double) |]
-  [| \(Variance a b c) -> (a,b,c)  |]
-  [| \(a,b,c) -> Variance a b c    |]
+  [| \(Variance a b c) -> (a,b,c)     |]
+  [| \(a,b,c) -> Variance a b c       |]
 
 derivingUnbox "MinD"
   [t| MinD -> Double |]
diff --git a/monoid-statistics.cabal b/monoid-statistics.cabal
--- a/monoid-statistics.cabal
+++ b/monoid-statistics.cabal
@@ -1,5 +1,5 @@
 Name:           monoid-statistics
-Version:        1.1.1
+Version:        1.1.2
 Cabal-Version:  >= 1.10
 License:        BSD3
 License-File:   LICENSE