Cost function

From Computer Science Wiki

Introduction[edit]

A cost function, also known as a loss function, is a mathematical function that measures the difference between the predicted output of a model and the true output. In the context of linear regression, the cost function measures the difference between the predicted values of the dependent variable based on the regression line and the actual observed values. The goal is to minimize the cost function, which represents the error or deviation between the predicted and true values. There are several commonly used cost functions in linear regression, including mean squared error and mean absolute error. The choice of the cost function depends on the problem and the goals of the analysis. The cost function is a critical component of the training process for machine learning algorithms, as it guides the optimization process to find the best parameters for the model.

A fairly decent video[edit]

Explain like I'm in 5th grade[edit]

Imagine you are baking a cake and you have a recipe that tells you how much sugar, flour, eggs and other ingredients to use. The recipe is like a plan that tells you how to make the cake. Now, let's say you accidentally put too much sugar in the cake, it's going to taste too sweet and might not be as good as it should have been.

A cost function is like a recipe for a machine learning model, it tells the model how to make predictions. The cost function helps the model learn from its mistakes and improve its predictions. Just like the cake, if the model makes a mistake, the cost function will tell how much of a mistake it made and how to fix it to make the predictions better.

So, just like the cake recipe, the cost function is a set of instructions that helps the model learn from its mistakes and get better at making predictions.