Added content

1 files changed, 25 insertions, 3 deletions

diff --git a/tutorials/module_4/2_data_processing.md b/tutorials/module_4/2_data_processing.md
index f969b2d..d75c35a 100644
--- a/tutorials/module_4/2_data_processing.md
+++ b/tutorials/module_4/2_data_processing.md
@@ -3,15 +3,37 @@
 ^7b1480
 
 
-## Data Cleaning and Filtering
+## Signal Processing - Filtering
 
+### Low-Pass
 
+### High-Pass
 
+### Band-Pass
 
+## Data Filtering
 
 
 
----
-## Reading & Writing Files
+## Data Cleaning
 
 
+### Empty Cells
+
+Remove data point - `df.dropna()`
+Replace data point - `fillna(130, inplace = True)`
+We can use this to replace each data point with mean, median or mode - 
+```python
+x = df["Calories"].mean()
+df.fillna({"Calories": x}, inplace=True)
+```
+
+
+
+### 
+
+
+
+Example
+https://www.w3schools.com/python/pandas/pandas_cleaning.asp
+