arXiv:0801.3905v1 [astro-ph] 25 Jan 2008 Average Properties of a Large Sample of z abs ∼ z em associated Mg II Absorption Line Systems Daniel Vanden Berk Department of Astronomy and Astrophysics, The Pennsylvania state University, 525 Davey Laboratory, University Park, PA 16802, USA Pushpa Khare Department of Physics, Utkal University, Bhubaneswar, 751004, India Donald G. York 1 Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637, USA Gordon T. Richards 2 Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA Britt Lundgren Department of Astronomy, University of Illinois at Urbana-Champaign, MC-221 1002 W. Green Street, Urbana, IL 61801, USA Yusra Alsayyad Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637, USA Varsha P. Kulkarni Department of Physics and Astronomy, University of South Carolina, Columbia, SC 29207, USA Mark SubbaRao 3 Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637, USA Donald P. Schneider