Hello Aditya,

Firstly ISI has generally batch strength of 30-40 stuents. But in the final list there are 65-75 students. Rest of the students reject the offer to join CMI/IIT/IISc. So it is easier than what you think. But don't take this seriously, because 65 is not enough.

So it is better not to prepare full time for it.

Interviews are generally consist of 6 to 7 professors of ISI Kolkata for B.Stat. They generally ask you to solve a question from subjective paper which you would not attempt. Then some questions of combinatorics , simple number theory may be asked. Try your best and control your nerve. Don’t be oversmart. Here luck really matters.

There are two papers in the written exam. Paper 1 covers Mathematics and is objective MCQ type questions.

Paper 1: Mathematics and Elementary Statistics

This section tests Class 11th and 12th level Maths focusing mainly on Algebra and Calculus.

The best way to prepare for it is to pick up RD Sharma or RS Aggarwal and revise the concepts and all the formulae. Once done, practice questions from past year Sample Papers. Another very useful source for practising is a book "Test of Mathematics at the 10+2 Level: Indian Statistical Institute" For elementary Statistics. You can brush up the concepts from any book like SC Gupta.

As I had done Science at 10+2 level and had also prepared for engineering entrances, I didn't find this section tough. But remember, this is the most important paper as, if you are unable to clear the cutoff in this Paper, your Paper 2 which is subjective won't be even marked. For those who are weak at Maths, you must put in a lot of effort.

Stage 2: Interview

Once you clear the written test, you will be called for an interview. It's a very simple process. I was given two questions, one of Maths and one of Economics and in 15 minutes I had to solve any one of them. After 15 minutes, I had to go in front of the interview panel and solve that sum on the board. That's it! If you are able to solve, you are selected. If you are unable to solve, you might not get selected. It's a do-or-a-die thing. There were absolutely no other questions. No questions on current affairs, no questions on why I want to do Masters, why ISI, etc.

Hope this will help.