ISI M. Stat. Admission Experience: A Nervous Yet Rewarding Journey

How was your ISI M. Stat. admission test 2019?

Hello, I am Yash Gupta from Tanda Ambedkar Nagar UP. I graduated in Statistics from Banaras Hindu University in 2019-22. This year, I appeared for the ISI M. Stat. entrance examination. Here is my interview experience, but if you are only interested in the experience, feel free to skip the first section to save time.

Background

After securing a satisfactory rank in IIT-JAM, I didn't put in much effort for the ISI entrance exam. I prepared for the written exam intensely for only a week right before the exam. My Performance in the Preliminary Selection Achievement (PSA) exam went well, but I was disappointed with my Performance in the Preliminary Selection Board (PSB). I almost lost hope that I would get selected for the interview. However, by the grace of God and with my brother, we got a chance to go to Delhi on June 16th for the ISI M. Stat. interview.

My interview was held in the afternoon session. We arrived at the ISI campus 4 hours prior to the reporting time. We were assigned to a room and got refreshed by having lunch at the mess. We were called to the auditorium at the reporting time. There were 12 students waiting for the interview. The interview session began at 2:40 PM, and my turn came after 150 minutes. Meanwhile, I clicked a few selfies with my brother in the almost vacant auditorium and chatted with friends online. After being called, I entered the interview room with nervousness.

Interview Process

There were three senior professors, P1, P2, and P3, each sitting 5 feet apart from each other, and a green board before them. Interview begins...

P2: Yash Gupta!

Me: Nodded. Good evening, sir.

P2: Come and sit on the chair. So, you are pursuing BSc in BHU.

Yes, sir!

Without much introduction, he went straight to the point.

P2: Tell me about the topic from which you want to be asked questions.

P2: Okay, then, do you know about Linear regression?

P2: A bit! If you don't tell the topic name, I will ask anything.

P2: So, you are comfortable with testing.

P2: Go and write on the board the conditions required for the density function.

I wrote:

- Should be 0 or 0

- Integration over the real line should be one.

In mathematical form.

P2: Can it be discontinuous?

Thought for a moment.

P2: Show how.

I gave a general example of the uniform distribution with discontinuity but made a big error.

P2: Are these the only conditions required?

P2: Hmm, can you show the graph of the pdf?

I thought for a moment and drew it on the board.

P1: Draw the CDF too.

I calculated it and drew it on the board.

Then he asked about the special case of the pdf which was Uab, then asked for the estimator of a and b based on a sample size n.

I started deriving MLEs of a and b by obtaining the joint likelihood function, but they stopped me as I said MLEs are consistent.

P2: MLEs are consistent.

I got confused.

P2: Can you define consistency?

I showed it on the board but took a long time. I was troubled a bit.

P2: Alright, you know it but couldn't have it at the moment.

Hmm, nodded.

P2 went out of the room.

P3: Have you read continuity and differentiability?

P2: Consider f and g be two continuous functions at point a. Will the product fg be continuous at point a?

Thought for a moment and said yes.

P2: Show on the board.

I started showing it but he stopped it in the middle as I wrote fxgx-fagx... I think he got the notion of what I am doing.

P3: Suppose F is discontinuous at point a and G is continuous at the same point a. What about FG?

I showed it by an example.

P3: If both are discontinuous. Then?

I showed it on the board.

P2 came back and looked toward P1.

P1: I want to ask a probability question.

P2: Okay.

P1: Suppose X~exp(1). What is the distribution of X^2.

I showed it by the CDF method.

P2: Your interview is over.

Great. Have you given JAM?

P2: What was your rank?

P2: Now you may leave.

I went out of the room with mixed emotions. Thinking of the interview, it lasted for almost 30 minutes. Just after me, my brother went in for his interview. I clicked a photo of him walking into the interview room. After 10 days, the merit list was uploaded on the website. And...

Yes, we both got selected, with me ranked 22 and my brother ranked 12. The thing I realized after both my ISI and IIT JAM exams is that...

Conclusion

I would like to thank my family, friends, professors, and Telegram who were part of my success story.