Styles of data analysis
What is the best way to begin investigation of a new set of data? What forms of data exploration will draw attention to obvious errors or quirks in the data, or to obvious clues that the data contain? What checks are desirable before proceeding with an intended formal analysis, or to help decide what formal analysis may be appropriate? What can be learned from investigations that other researchers have done with similar data?
Competent statisticians have always used graphs to check their data. Numerical summaries, such as an average, can be very useful, but important features of the data may be missed without a glance ...