Cross Validation

"Cross Validation" Anyone who has just started dabbling in the world of Data Science must have seen this term. In this article cross validation, the need for cross validation, and some types of cross validation will be explained in very simple words. Let's just start with a basic question before going into details. Well, it helps us to compare different machine learning algorithms. To evaluate how well a machine learning algorithm is working we need to train the algorithm on some part of data (known as "Training Data") and to test on unseen data (known as "Testing Data").