fix numbering

content/chapters/20_imbalanced_learning/20-03-cs-1.md

@@ -1,6 +1,6 @@
 ---
-title: "Chapter 21.03: Cost-Sensitive Learning 1"
-weight: 21003
+title: "Chapter 20.03: Cost-Sensitive Learning 1"
+weight: 20003
 ---
 We introduce the concept of a Cost Matrix, the Minimum expected cost priciple and the optimal theoretical threshold.
 <!--more-->

content/chapters/20_imbalanced_learning/20-04-cs-2.md

@@ -1,6 +1,6 @@
 ---
-title: "Chapter 21.04: Cost-Sensitive Learning 2"
-weight: 21004
+title: "Chapter 20.04: Cost-Sensitive Learning 2"
+weight: 20004
 ---  
 In this section we focus on empirical thresholding and model-agnostic Meta Costs.
 <!--more-->

content/chapters/20_imbalanced_learning/20-09-smpl-2.md

@@ -1,6 +1,6 @@
 ---
-title: "Chapter 21.09: Sampling Methods 2"
-weight: 21009
+title: "Chapter 20.09: Sampling Methods 2"
+weight: 20009
 ---
 We introduce the state-of-art oversampling technique SMOTE.
 <!--more-->

content/chapters/20_imbalanced_learning/21-03-cs-1.md

@@ -0,0 +1,15 @@
+---
+title: "Chapter 20.03: Cost-Sensitive Learning 1"
+weight: 20003
+---
+We introduce the concept of a Cost Matrix, the Minimum expected cost priciple and the optimal theoretical threshold.
+<!--more-->
+
+### Lecture video
+
+{{< video id="Yc1uWlRLdPU" >}}
+
+### Lecture slides
+
+{{< pdfjs file="https://github.com/slds-lmu/lecture_advml/blob/main/slides-pdf/slides-imbalanced-learning-cost-sensitive-learning-1.pdf" >}}
+

content/chapters/20_imbalanced_learning/21-04-cs-2.md

@@ -0,0 +1,15 @@
+---
+title: "Chapter 20.04: Cost-Sensitive Learning 2"
+weight: 20004
+---  
+In this section we focus on empirical thresholding and model-agnostic Meta Costs.
+<!--more-->
+
+### Lecture video
+
+{{< video id="aPYUKBaSLOo" >}}
+
+### Lecture slides
+
+{{< pdfjs file="https://github.com/slds-lmu/lecture_advml/blob/main/slides-pdf/slides-imbalanced-learning-cost-sensitive-learning-2.pdf" >}}
+