diff --git a/src/Psl/Math/max.php b/src/Psl/Math/max.php
index 8596ea00..eaf90f50 100644
--- a/src/Psl/Math/max.php
+++ b/src/Psl/Math/max.php
@@ -12,7 +12,7 @@
  *
  * @param list<T> $numbers
  *
- * @return T|null
+ * @return ($numbers is non-empty-list<T> ? T : null)
  *
  * @pure
  */
diff --git a/src/Psl/Math/mean.php b/src/Psl/Math/mean.php
index fdeaba98..36d83c73 100644
--- a/src/Psl/Math/mean.php
+++ b/src/Psl/Math/mean.php
@@ -13,6 +13,8 @@
  *
  * @param list<int|float> $numbers
  *
+ * @return ($numbers is non-empty-list<int|float> ? float : null)
+ *
  * @pure
  */
 function mean(array $numbers): ?float
diff --git a/src/Psl/Math/median.php b/src/Psl/Math/median.php
index f6a7a6b4..2ed9db86 100644
--- a/src/Psl/Math/median.php
+++ b/src/Psl/Math/median.php
@@ -14,6 +14,8 @@
  *
  * @param list<int|float> $numbers
  *
+ * @return ($numbers is non-empty-list<int|float> ? float : null)
+ *
  * @pure
  */
 function median(array $numbers): ?float
diff --git a/src/Psl/Math/min.php b/src/Psl/Math/min.php
index 082d8a96..6e6a97b4 100644
--- a/src/Psl/Math/min.php
+++ b/src/Psl/Math/min.php
@@ -12,7 +12,7 @@
  *
  * @param list<T> $numbers
  *
- * @return T|null
+ * @return ($numbers is non-empty-list<T> ? T : null)
  *
  * @pure
  */