Statistical Analysis with Excel For Dummies, 5th Edition

Chapter 16

It’s About Time

IN THIS CHAPTER

Understanding time series

Moving averages

Smoothing things out

Forecasting with just one (?) click

Working with time series on the iPad

In many fields (science, medicine, business), it’s often necessary to take measurements over successive intervals of time. When you have this kind of data, you have yourself a time series. This chapter tells you about time series and how to use Excel to understand them and use them to make forecasts.

A Series and Its Components

Managers often have to base their decisions on time series — like sales figures — and the numbers in a time series typically show numerous ups and downs.

Here’s an example. The (totally fictional) FarDrate Timepiece Corporation markets the beautifully designed MeesKyte watch, and company leaders gather the quarterly national sales figures. Figure 16-1 shows a spreadsheet and a graph of these sales figures from 2016–2020.

Take a look at the graph. The peaks and valleys seem pretty ...