Machine learning fundamentals

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1. Cost Function. (Understanding and calculating Cost Function.)

In machine learning, Linear regression is one of the most used algorithms. Cost Function and Gradient Descent form a linear regression model.

What is a Cost Function?

Cost functions are used to estimate how badly models are performing i.e. measure the performance of a machine learning model for given data.

This is through quantifying the error between predicted and expected values and presenting them in form of a real number.

Here is an example of a table of data with its graph:

original data graph

The table below contains samples of hypotheses values. Given the hypotheses our goal is to find the line of best fit to the graph above. (This is an example of a supervised learning problem)