Error Metrics in Machine learning

If you are reading this blog, you will probably be familiar with machine learning or will be interested in learning the same. Machine learning is a subfield of artificial intelligence, where it makes the systems to learn from data and make them capable of taking decisions with minimal human intervention. Now generally, we use the word "model" to indicate this intelligent system. Now, suppose we have a model which is designed to perform a particular task. This task can be anything like, for example, classifying the emails as not spam and spam, or an image classification problem.