Time-Series Diagram

In this tutorial you're going to learn about time-series diagrams. We will cover:

1. Time-Series Diagrams

1. Time-Series Diagrams

Time-series diagrams are among the most common graphs that you're going to see in everyday life.

Time-Series Diagram

A graphical display that shows the values a variable takes over time.

Time-series graphs are particularly useful for showing how information changes over time.

IN CONTEXT

You have probably seen time-series graphs almost every day in the stock market report in the business section of the newspaper.This is a graph of the price of a stock over the course of several months October, November, December, January.



This graph shows that the stock price has been going up and down but then during the first couple months of 2012 started getting high again. So the graph demonstrates the different value that a variable takes over the course of time.

The time-series graph allows you to see certain values that you might not be able to see in some other kind of graphical display.

Take a look at this histogram of high temperatures over the course of the year. There are 365 different values from the National Weather Service for Chanhassen, Minnesota, binned by 10s.

Now compare this histogram with a time-series diagram of the same data:

Both graphs contain the same information. But in the time-series graph, you can see this data over time.

The histogram shows you that the most common temperature throughout the year in Chanhassen, Minnesota was in the 70s, between 70 and 80 degrees. It happened about 80 times.

You can also see that on the time series. You'd need to look horizontally between 60 and 70 on the vertical axis, and make horizontal lines over to see how many points were within that band. Doing so would show that there were lots and lots of points within that band.

Additionally this shows how the temperature tends to change over the course of the year. It gets high in the middle of the year unsurprising because it's summer. And then gets slow at both the beginning and the end of the year, bottoming out in early January. This additional trend is something that you don't see on the histogram.

A time-series diagram will show the change of a value over time. Time-series are not only useful in telling you what the data values are but also when they occurred. They can show you additional information that other plots might not.

Thank you and good luck!