Data Smart: Using Data Science to Transform Information into Insight

it's relatively easy to compute prediction intervals around exponential smoothing forecasts, so you're going to do a bit of that too. Getting Acquainted with Time Series Data NOTE The Excel workbook used in this chapter, “SwordForecasting.xlsm,” is available for download at the book's website at www.wiley.com/go/datasmart.

All you need to do is when you're done typing the formula, instead of pressing Enter, press Ctrl+Shift+Enter. On the Mac, you use Command+Return.

This devil's advocate assumption is called the null hypothesis. The standard practice is to reject the null hypothesis if given it were true, the probability of obtaining a fit at least this good is less than 5 percent. This probability is often called a p value.

just cleverly turns past data into a formula or set of rules that it uses to predict a future case. As we saw in the case of naïve Bayes in Chapter 3, it's the AI model's ability to recall this data and associated decision rules, probabilities, or coefficients that make it so effective.

Identify the analytics opportunities you want to tackle in as much detail as possible before acquiring tools.

“Why didn't you use support vector machines or neural nets or random forests or boosted trees?” There are numerous types of AI models all with their strengths and weaknesses. And I would encourage you to read about them, and if in your

forecast growth as best we can so that we can plan our infrastructure and HR pipelines. You don't always want to be playing catch-up.

You get more bang for your buck spending your time on selecting good data and features than models.

media. One example is the congressional discussion around NSA's ability to perform a “three-hop” query—that is go into their network graph of phone call data and find people three hops from a known terrorist (nodes connected to a terrorist by a three edge path in the graph). Whatever your business is, I guarantee you have a graph hiding in your dat

So whether we're talking sending coupons in the mail, approving loans, or dropping bombs, the balance you strike between these performance metrics is a strategic decision. Comparing One Model