The most important units ( numerical wise)
1. Central Tendencies
2. General concepts of distributions like bayes theorem, binomial, pascal, poisson, normal etc.
3. Correlation & regression
Beside these, prepare small logics too from:
1. A.P. & G.P.
2. Limit and continuity
3. Differentiation and applications of derivatives ( Marginal revenues, average costs etc. Part C of R.S. Aggarwal from 12th standard will be useful)
4. Unit 3 from I.G.N.O.U Books
Just have a look on the given solved examples of these units from I.G.N.O.U books
and ofcourse previous years TEE papers.