cal disparity in promotions is statistically significant at 2.54 standard deviations from what would be expected if race were a neutral factor. See Hazelwood Sch. Dist. v. United States, 433 U.S. 299, 308 n. 14, 97 S. Ct. 2736, 53 L. Ed. 2d 768 (1977) (indicating that anything greater than two or three stand