US Court of Appeal for the Second Circuit applied US Supreme Court's opinion (Reeves v. Sanderson Plumbing Inc. and McDonnell Douglas Corp. v. Green) that "The plaintiff must first establish a prima facie case of discrimination. Once the plaintiff has met the minimal burden of establishing a prima facie case, the burden then shifts to the defendant to produce a legitimate, nondiscriminatory reason for the adverse employment action. The burden then shifts back to the plaintiff to show that the proffered reason was pretextual and that the defendant discriminated against the plaintiff" http://findarticles.com/p/articles/mi_qn4180/is_20010620/ai_n10066999
So, in the above case, initially it is the burden of the employees to show that they had been discriminated by Texaco and later, burden of proof lies with the employer to demonstrate justifiable nondiscriminatory reasons supported by statistics that the decision was not influenced by discrimination (Zimmermann v. Associates First Capital Corporation).
In 1973, the case of McDowell Douglas Corporation v. Green the Supreme Court established the burden of proof (Title VII) as a model by opining: Plaintiff carries the initial burden establishing that he/she belongs to a protected group, is qualified for the job, and was rejected while post remained vacant, and then burden shifts to employer to justify himself (St.