Data Science on the Google Cloud Platform, 2nd Edition

Chapter 1. Making Better Decisions Based on Data

The primary purpose of data analysis is to make better decisions. There is rarely any need for us to spend time analyzing data if we aren’t under pressure to make a decision based on the results of that analysis. When you are purchasing a car, you might ask the seller what year the car was manufactured and the odometer reading. Knowing the age of the car allows you to estimate the potential value of the car. Dividing the odometer reading by the age of the car allows you to discern how hard the car has been driven, and whether it is likely to last the five years you plan to keep it. Had you not cared about purchasing the car, there would have been no need for you to do this data analysis.

In fact, we can go further—the purpose of collecting data is, in many cases, only so that you can later perform data analysis and make decisions based on that analysis (see Figure 1-1). When you asked the seller the age of the car and its mileage, you were collecting data to carry out your data analysis. But it goes beyond your data collection. The car has an odometer in the first place because many people, not just potential buyers, will need to make decisions based on the mileage of the car. The odometer reading needs to support many decisions—should the manufacturer pay for a failed transmission? Is it time for an oil change? The analysis for each of these decisions is different, but they all rely on the fact that the mileage data has been