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Intern Data Scientist interview questions shared by candidates

## Top Interview Questions

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Data Scientist Intern was asked...25 February 2012

### Find the second largest element in a Binary Search Tree

The above answer is also wrong; Node findSceondLargest(Node root) { // If tree is null or is single node only, return null (no second largest) if (root==null || (root.left==null &amp;&amp; root.right==null)) return null; Node parent = null, child = root; // find the right most child while (child.right!=null) { parent = child; child = child.right; } // if the right most child has no left child, then it's parent is second largest if (child.left==null) return parent; // otherwise, return left child's rightmost child as second largest child = child.left; while (child.right!=null) child = child.right; return child; } Less

find the right most element. If this is a right node with no children, return its parent. if this is not, return the largest element of its left child. Less

One addition is the situation where the tree has no right branch (root is largest). In this special case, it does not have a parent. So it's better to keep track of parent and current pointers, if different, the original method by the candidate works well, if the same (which means the root situation), find the largest of its left branch. Less

### Given two lists of sorted integers, develop an algorithm to sort these numbers into a single list efficiently.

This might be solved by using a similar logic we used for the merge procedure in merge sort Less

The key in these questions is to cover the fundamentals, and be ready for the back-and-forth with the interviewer. Might be worth doing a mock interview with one of the Quora or ex-Quora Data Scientist Intern experts on Prepfully? They give real-world practice and guidance, which is pretty helpful. prepfully.com/practice-interviews Less

I think what SAS does to this issue could be referred as one solution

### 15 mins with an HR Recruiter followed by 1 Hour Technical Interview with 3 Data Scientist's - Case Studies on Sales Prediction. The interviewers were knowledgeable and the questions they asked were relevant to the intern job requirements.

Brieflfy

can you give more details?

### For the first round audio interview: 1. multicollinearity 2. decision trees 3. end-to-end method for deep learning on a genomic dataset For the video interview: 1. what is the most challenging aspect of data science projects for you 2. describe projects on resume 3. how do you communicate

Can you please tell me when you heard back from them after the hirevue interview? Less

### How would you avoid over-fitting from a machine learning model ? Describe different methods

Drop-out technique in deep neural networks

1. Add a regularisation term 2. Use test data and do cross validation (like k-fold) 3. Use PCA and SVD to reduce dimensionality. Less

### Case study question and simple SQL questions.

May I know how many rounds of interview did u take? Thank u

Hey, do you mind if you provide a bit more info on your round two and three questions? Thanks a lot! Less

### Are you a hard worker or a smart worker?

Hard worker

I choose hardworking or over smart work because hardworking never fails..

### Qual sua familiaridade com projetos usando Machine Learning.

Minha iniciação científica.