Guides  /  ,

Summary Statistics Tell You Little About the Big Picture

By Nathan Yau

Mean, median, and mode. These are the first things you learn about in your introductory statistics course. It’s often all you hear about when you see data in the news. People form policies for populations, based on the generalized numbers.

However, these summary statistics can only tell you so much about a dataset, which means you can only learn a limited amount about what the data represents — the people, places, and things.

If you’re the one who consumes the data, you should wonder what the means and medians actually represent. If you’re the one who analyzes the data, spend time with the most granular that time and resources allow for. Something more interesting will almost always come out of it.

Chart Type Used

Histogram

It looks like a bar chart, but it reads differently. The baseline is continuous instead of discrete categories, which allows one to see distributions.

Favorites

Reviving the Statistical Atlas of the United States with New Data

Due to budget cuts, there is no plan for an updated atlas. So I recreated the original 1870 Atlas using today’s publicly available data.

Watching the growth of Walmart – now with 100% more Sam’s Club

The ever so popular Walmart growth map gets an update, and yes, it still looks like a wildfire. Sam’s Club follows soon after, although not nearly as vigorously.

Divorce Rates for Different Groups

We know when people usually get married. We know who never marries. Finally, it’s time to look at the other side: divorce and remarriage.

Visualizing the Uncertainty in Data

Data is an abstraction, and it’s impossible to encapsulate everything it represents in real life. So there is uncertainty. Here are ways to visualize the uncertainty.