v. Am. Nat'l Bank, 652 F.2d 1176, 1192 (4th Cir. 1981); see also Kingsley R. Browne, Statistical Proof of Discrimination: Beyond "Damned Lies", 68 Wash. L. Rev. 477, 503 (1993) ("Random disparities of this magnitude are pervasive in the workplace and are not suggestive of a nonrandom cause, let alone an ille