Merge pull request #924 from yukthagangadhari5/docs-regression-beginner-note

docs: add beginner note explaining linear regression

2-Regression/3-Linear/README.md

@@ -1,5 +1,11 @@
 # Build a regression model using Scikit-learn: regression four ways
 
+## Beginner Note
+
+Linear regression is used when we want to predict a **numerical value** (for example, house price, temperature, or sales).
+It works by finding a straight line that best represents the relationship between input features and the output.
+
+In this lesson, we focus on understanding the concept before exploring more advanced regression techniques.
 ![Linear vs polynomial regression infographic](./images/linear-polynomial.png)
 > Infographic by [Dasani Madipalli](https://twitter.com/dasani_decoded)
 ## [Pre-lecture quiz](https://ff-quizzes.netlify.app/en/ml/)