diff --git a/education/statistics/random-variable.html b/education/statistics/random-variable.html
index 6c0d6aa..1bee212 100644
--- a/education/statistics/random-variable.html
+++ b/education/statistics/random-variable.html
@@ -2,7 +2,7 @@
 title: 隨機變數 (Random Variable)
 description: 
 published: true
-date: 2025-12-28T17:34:08.898Z
+date: 2025-12-28T19:13:54.913Z
 tags: 
 editor: ckeditor
 dateCreated: 2025-12-28T16:41:51.938Z
@@ -12,7 +12,7 @@ dateCreated: 2025-12-28T16:41:51.938Z
 <h3><span style="font-family:Arial, Helvetica, sans-serif;">Probability Mass Function (PMF)</span></h3>
 <p><span style="font-family:Arial, Helvetica, sans-serif;">A set of probability value <strong>p<sub>i</sub></strong> assigned to each of the values taken by the discrete random variables <strong>x<sub>i</sub></strong>.</span></p>
 <p><strong>0 ≤ p<sub>i</sub> ≤ 1 and ∑ p<sub>i</sub> = 1</strong></p>
-<p><span style="font-family:Arial, Helvetica, sans-serif;">Probability</span><br>&nbsp;</p>
+<p><span style="font-family:Arial, Helvetica, sans-serif;">Probability</span><br>&nbsp;$$\leq$$</p>
 <p><span style="font-family:Arial, Helvetica, sans-serif;">Expectation</span><br>&nbsp;</p>
 <h3><span style="font-family:Arial, Helvetica, sans-serif;">Cumulative Distribution Function (CDF)</span></h3>
 <p><br>&nbsp;</p>