Data Scientist Interview Questions

Erjan G. - "1) select avg(session) from table where session> 180 2) select round(sessiontime/300)*300 as sessionbin, count() as sessioncount from table group by round(sessiontime/300)300 order by session_bin 3) SELECT t1.country AS country_a, t2.country AS country_b FROM ( SELECT country, COUNT(*) AS session_count FROM yourtablename GROUP BY country ) AS t1 JOIN ( SELECT country, COUNT(*) AS session_count FROM yourtablename `GROUP BY countr"See full answer

Judy W. - "Situation: COVID has impacted everyone's lives, especially small businesses. Earlier this year, during the second lockdown in Malaysia, it was estimated that 50%-70% of small businesses have closed. It got me thinking, beyond the existing training programmes, what can my company do to support small businesses? Task: So, I took the initiative to gather our Comms and Government Affairs team, to work together and explore how we can: 1) meaningfully demonstrate our company's commitment in"See full answer

Yuexiang Y. - "clarify: so does the 5% drop a sudden drop or overtime in the one week does it broadly drop 5% or it dropped only in some regions or in some segments like new acqusition / frequent active customers? or does the 5% drop also happened last year same period? DAU = acqusition x activation x retention segment: I will first quickly do some EDA to find out problem, like calculate the DAU drop in new customer, tenured customer, between regions to find out is there any difference. then I will also look"See full answer

Ritaban M. - " Brute Force Two Pointer Solution: from typing import List def two_sum(nums, target): for i in range(len(nums)): for j in range(i+1, len(nums)): if nums[i]+nums[j]==target: return [i,j] return [] debug your code below print(two_sum([2, 7, 11, 15], 9)) `"See full answer

Rick E. - " from typing import List def getnumberof_islands(binaryMatrix: List[List[int]]) -> int: if not binaryMatrix: return 0 rows = len(binaryMatrix) cols = len(binaryMatrix[0]) islands = 0 for r in range(rows): for c in range(cols): if binaryMatrixr == 1: islands += 1 dfs(binaryMatrix, r, c) return islands def dfs(grid, r, c): if ( r = len(grid) "See full answer

Ranj A. - "In the Transformer architecture, the decoder differs from the encoder primarily in its additional mechanisms designed to handle autoregressive sequence generation. Here's a breakdown of the key differences: Self-Attention Mechanism: Encoder: The encoder has a standard self-attention mechanism that allows each token to attend to all other tokens in the input sequence. Decoder: The decoder has two types of self-attention. The first is the same as in the encoder, but the second is mas"See full answer

G B. - " select user_id, b.marketing_channel from user_sessions a Left join attribution b on b.sessionid = a.sessionid group by 1,2 HAVING sum(purchasevalue)>100 and min(adclick_timestamp) `"See full answer

Vineet M. - "I'd hypothesize it's a highly right-skewed, long-tail distribution. This is because the user base is a mix of a huge number of 'casual' users who make very few queries and a small number of 'power' users who make a ton."See full answer

Apurv M. - "Situation (S) I was leading the greenfield development of an AI-driven Supply Chain Control Tower for a major medical equipment manufacturer. The business priority was "First Mover Advantage," requiring a Beta release for three pilot hospitals within a compressed 5-month timeline. To hit this window, we initially chose a Low-Code (Power Pages) architecture for its auto-scaling and rapid deployment capabilities. Task (T) Post-Beta, the Marketing team rejected the UI/"See full answer

Saurabh K. - "Goals : Determine if the TV series should be renewed If it should be renewed, how much should Netflix be willing to pay for this series Let's assume that the goal is to maximize subscriber retention and engagement while paying a reasonable amount for the licensing costs that is justified by the value added by the series. Assumptions : The show is exclusive to Netflix for a particular region (for eg. US) It has been on the platform for an year Netflix has subscriber level data around"See full answer

Manaswini D. - "user surveys and interviews: Ask users how well the reactions reflect their feelings. sentiment analysis : Analyze comment sentiment to see if it aligns with reactions. Machine learning classification model: Train models to predict user emotion from post content and compare with selected reactions."See full answer

Jeff S. - " function findPrimes(n) { if (n 1; i--) { if (num % i === 0) { notPrimes.add(num); return false; } } return true; } for (let i = 2; i 5 && !notPr"See full answer

Abdurhman M. - "If you effectively listen and understand their point of view, then take action to address the issue quickly. Don't let too much time slip between the conflict and the resolution. If resolving the concern will take more time, communicate the current status and next steps with the stakeholder."See full answer

Cagdas A. - " class ListNode: def init(self, val=0, next=None): self.val = val self.next = next def has_cycle(head: ListNode) -> bool: pass # your code goes here if head is None: return False previousNodes = set() iter = head while iter: if iter.val in previousNodes: return True previousNodes.add(iter.val) iter = iter.next; return False debug your code below node1 = ListNode(1) node2 = ListNode(2) n"See full answer

Jerry O. - "\# Definition for a binary tree node. class TreeNode: def init(self, val=0, left=None, right=None): self.val = val self.left = left self.right = right class Solution: def maxPathSum(self, root: TreeNode) -> int: self.max_sum = float('-inf')"See full answer

Bhavna S. - " with youngsuccrate as( select strftime('%m', postdate) AS postmonth, round(sum(issuccessfulpost)*1.0/count(issuccessfulpost),2)as yascrate from post where userid in (select userid from post_user where age between 0 and 18) group by post_month ), nonyoungsucc_rate as( select strftime('%m', postdate) AS postmonth, round(sum(issuccessfulpost)*1.0/count(issuccessfulpost),2)as nonyasc_rate from post where user_id in (select"See full answer