Here's a slide on it https://s3.amazonaws.com/content.udacity-data.com/courses/ud810/slides/Unit-2/2B-L1.pdf https://s3.amazonaws.com/content.udacity-data.com/c

Here's a slide on it https://s3.amazonaws.com/content.udacity-data.com/courses/ud810/slides/Unit-2/2B-L1.pdf https://s3.amazonaws.com/content.udacity-data.com/courses/ud... Basically, it's used to find parameters to a model with sample data.