diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 34b6343..a42596f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -51,7 +51,7 @@ jobs:
       name: Cache ~/.cabal/store
       with:
         path: ${{ steps.setup-haskell-cabal.outputs.cabal-store }}
-        key: ${{ runner.os }}-${{ matrix.ghc }}--${{ github.Shah }}-CACHE_V3
+        key: ${{ runner.os }}-${{ matrix.ghc }}---CACHE_V3
     # ----------------
     - name: "Install PAPI"
       run: |
diff --git a/Statistics/Test/ChiSquared.hs b/Statistics/Test/ChiSquared.hs
index c5be9fc..1c7ed9e 100644
--- a/Statistics/Test/ChiSquared.hs
+++ b/Statistics/Test/ChiSquared.hs
@@ -17,8 +17,8 @@ import Statistics.Types
 import qualified Data.Vector as V
 import qualified Data.Vector.Generic as G
 import qualified Data.Vector.Unboxed as U
-
-
+import qualified Data.Vector.Fusion.Bundle as F
+import qualified Numeric.Sum as Sum
 
 -- | Generic form of Pearson chi squared tests for binned data. Data
 --   sample is supplied in form of tuples (observed quantity,
@@ -26,7 +26,7 @@ import qualified Data.Vector.Unboxed as U
 --
 --   This test should be used only if all bins have expected values of
 --   at least 5.
-chi2test :: (G.Vector v (Int,Double), G.Vector v Double)
+chi2test :: (G.Vector v (Int,Double))
          => Int                 -- ^ Number of additional degrees of
                                 --   freedom. One degree of freedom
                                 --   is due to the fact that the are
@@ -44,7 +44,10 @@ chi2test ndf vec
   | otherwise = Nothing
   where
     n     = G.length vec - ndf - 1
-    chi2  = sum $ G.map (\(o,e) -> square (fromIntegral o - e) / e) vec
+    chi2  = Sum.kbn
+          $ F.foldl' Sum.add Sum.zero
+          $ F.map (\(o,e) -> square (fromIntegral o - e) / e)
+          $ G.stream vec
     d     = chiSquared n
 {-# INLINABLE  chi2test #-}
 {-# SPECIALIZE
@@ -56,7 +59,7 @@ chi2test ndf vec
 -- | Chi squared test for data with normal errors. Data is supplied in
 --   form of pair (observation with error, and expectation).
 chi2testCont
-  :: (G.Vector v (Estimate NormalErr Double, Double), G.Vector v Double)
+  :: (G.Vector v (Estimate NormalErr Double, Double))
   => Int                                   -- ^ Number of additional
                                            --   degrees of freedom.
   -> v (Estimate NormalErr Double, Double) -- ^ Observation and expectation.
@@ -71,5 +74,8 @@ chi2testCont ndf vec
   | otherwise = Nothing
   where
     n     = G.length vec - ndf - 1
-    chi2  = sum $ G.map (\(Estimate o (NormalErr s),e) -> square (o - e) / s) vec
+    chi2  = Sum.kbn
+          $ F.foldl' Sum.add Sum.zero
+          $ F.map (\(Estimate o (NormalErr s),e) -> square (o - e) / s)
+          $ G.stream vec
     d     = chiSquared n
diff --git a/changelog.md b/changelog.md
index dd1f56c..bff0b21 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,12 +1,12 @@
-## Unreleased
+## Changes in 0.16.4.0 [2025.10.23]
 
-- **New Features**:
-  - Implemented Bartlett's test (`Statistics.Test.Bartlett`) for homogeneity of variances.
-  - Implemented Levene's test (`Statistics.Test.Levene`) for homogeneity of variances.
-  - Resolves [#137](https://github.com/haskell/statistics/issues/137).
+ * Bartlett's test (`Statistics.Test.Bartlett`) and Levene's test
+   (`Statistics.Test.Levene`) for homogeneity of variances is added.
+
+ * Improved performance in calculation of moments.
+
+ * Improved precision in calculation of `logDensity` of Student T distribution.
 
-- **Documentation**:
-  - Added usage examples and Haddock comments for both tests.
 
 ## Changes in 0.16.3.0
 
diff --git a/statistics.cabal b/statistics.cabal
index 8f01857..4bb5c9f 100644
--- a/statistics.cabal
+++ b/statistics.cabal
@@ -2,7 +2,7 @@ cabal-version:  3.0
 build-type:     Simple
 
 name:           statistics
-version:        0.16.3.0
+version:        0.16.4.0
 synopsis:       A library of statistical types, data, and functions
 description:
   This library provides a number of common functions and types useful
@@ -137,7 +137,7 @@ library
                , binary                  >= 0.5.1.0
                , primitive               >= 0.3
                , dense-linear-algebra    >= 0.1 && <0.2
-               , parallel                >= 3.2.2.0 && <3.3
+               , parallel                >= 3.2.2.0 && <3.4
                , vector                  >= 0.10
                , vector-algorithms       >= 0.4
                , vector-th-unbox
@@ -174,6 +174,8 @@ test-suite statistics-tests
     Tests.Quantile
   ghc-options:
     -Wall -threaded -rtsopts -fsimpl-tick-factor=500
+  if impl(ghc >= 9.8)
+    ghc-options: -Wno-x-partial
   build-depends: base
                , statistics
                , dense-linear-algebra