Ellen currently lives in Belgium, Brussels where she has been since 2001. Until 2008 she worked at the International School of Brussels as Head of the High School and as a teacher of AP Statistics and IB Math Standard Level. She has also taught high school mathematics at Sandy Spring Friends School and at Sidwell Friends School in Washington, D.C. At the college level, Ellen has taught statistics at California State University Sacramento and at George Washington University in Washington, D.C. She has worked as a mathematical statistician for the Internal Revenue Service. Ellen has a Master’s degree in mathematical statistics from the University of California at Davis and all but a dissertation (ABD) in mathematical statistics from George Washington University in Washington, DC. Ellen has worked for CK-12 since 2008 as a reviewer and author. In addition to this work she teaches a semester course, Statistics for Lawyers, at the University of California at Irvine School of Law and is an IB Examiner for Mathematics Standard Level.