A collection of Sage code to compute the average value of various invariants of elliptic curves ordered by height. This code was (initially) written at the MRC 2012 Arithmetic Statistics workshop by Jennifer Balakrishnan, Nathan Kaplan, Simon Spicer and Jamie Weigandt, under the direction of Wei Ho.
The code is written in .sage files. To access it's functionality, from within Sage navigate into the directory containing curves_by_height.sage and four_selmer.sage, and type:
sage: attach curves_by_height.sage
The various methods in the file will then be accessible at the command level.