This chart shows a histogram of a log-normal distribution of time durations. The data is randomly generated: each value is a number representing a duration measured in minutes. The values are then binned at regular intervals using D3’s histogram layout. A custom tick format for the x-axis converts these numbers to dates before passing them through a d3.time.format. The x-axis uses a linear scale, such that the tick values appear in-between bars; this provides better indication that each bar represents the count of values between its surrounding tick values.
See also this histogram of an Irwin–Hall distribution.