Underfitting vs. Overfitting in Machine Learning - Analytics Vidhya

Can you explain what is underfitting and overfitting in the context of machine learning? Describe it in a way even a non-technical person will grasp. Your ability to explain this in a non-technical and easy-to-understand manner might well decide your fit for the data science role! Even when we're working on a machine learning project, we often face situations where we are encountering unexpected performance or error rate differences between the training set and the test set (as shown below). How can a model perform so well over the training set and just as poorly on the test set?