6. Exploring Data with Simple Charts
The greatest value of a picture is when it forces us to notice what we never expected to see.
—John W. Tukey, Exploratory Data Analysis
The famous statistician John W. Tukey once wrote that exploring data is “graphical detective work.”1
1 These are the first lines in Tukey’s 1977 classic Exploratory Data Analysis.
Tukey created an entire branch of data analysis almost singlehandedly. He called it exploratory data analysis. He explained that, before you can even begin testing your ideas against the evidence, it’s essential to get a good feel for what your data look like. And the best way of doing so involves graphical displays, not just numerical summaries.
It would be presumptuous on my part to assume that ...