Time-Series Diagram

Video Transcription

In this tutorial you're going to learn about time series diagrams. Now time series diagrams are among the most common graphs that you're going to see in everyday life. You see them almost every day in the stock market 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. It looks like this stock price has been going up and down but then during the first couple months of 2012 started getting high again. You've seen this on multiple graphs newspaper, online, they're all over the place. And all it shows is the different value that a variable takes over the course of time.

And it allows you to see certain values that you might not be able to see in some other kind of graphical display. For instance, take a look at this histogram of high temperatures over the course of the year. There are 365 different values here binned to by 10s for Chanhassen, Minnesota. This is from the National Weather Service.

And this is that same data in a time series. What you can see is you can see all the same information that you would see on a histogram. But you can see it over time. So, for instance, 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'd have to look a little bit more closely. But you would see that's also the case here on the time series. You'd need to look horizontally between 60 and 70 on this axis, the vertical axis, and make horizontal lines over to see how many points were within that band. And you would see 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. And it's some nice additional information to have.

So to recap a time series will show the change of a value over time. And if that's something that you're interested in this is a good choice to use. Time series are not only useful in telling you what the data values are but also when they occurred. They can show you some additional information that other plots might not. The vocab we used in this lesson were time series. Good luck. And we'll see you next time.