Cognizant Programme Analyst interview questions

Tell me about yourself? technical questions according to the job profile. personality and confidence checking questions. online Aptitude test which consists of questions like basic English, Quantitative questions and reasoning questions. you have to be clear with the knowledge you are having and the resume should be updated and clear.

Applied through campus recruitment.First was aptitude test by amcat, then technical and HR interview. But, as from EC background, interviewer directly told he want only students from cs background. Then why do they call students from other background?