Learn Gradient Descent (with code)

Lots of statistics and machine learning involves turning a bunch of data into new numbers to make good decisions. For example, a data scientist might use your past bids on a Google search term, and the results, to work out the expected return on investment (ROI) for new bids. Armed with this knowledge you can make an informed decision about how much to bid in the future. Cool, but what if those ROIs are wrong? Luckily, data scientists don't just guess these numbers! They use data to generate a reasoned number for them.