Data Interview Questions

How can you tell if a given coin is biased?

Data Scientist

Interviewed at Google

4.4★

Mar 5, 2018

How can you tell if a given coin is biased?

Lets say the population on Facebook clicks ads with a click-through-rate of P. We select a sample of size N and examine the sample's conversion rate, denoted by hat{P}, what is the minimum sample size N such that Probability( ABS(hat{P} - P) < DELTA ) = 95%. In other words (this is my translation), find the minimum sample size N such that our sample estimate hat{P} is within DELTA of the true click through rate P, with 95% confidence.

Data Scientist, Analytics

Interviewed at Meta

3.6★

Mar 6, 2015

Lets say the population on Facebook clicks ads with a click-through-rate of P. We select a sample of size N and examine the sample's conversion rate, denoted by hat{P}, what is the minimum sample size N such that Probability( ABS(hat{P} - P) < DELTA ) = 95%. In other words (this is my translation), find the minimum sample size N such that our sample estimate hat{P} is within DELTA of the true click through rate P, with 95% confidence.

Given 25 swimmers and a pool with five lanes, what is the minimum number of heats needed to determine the three fastest swimmers in the group?

Data Scientist

Interviewed at CKM Analytix

2.9★

Nov 13, 2014

Given 25 swimmers and a pool with five lanes, what is the minimum number of heats needed to determine the three fastest swimmers in the group?

Many personality questions and situation based question (i.e. What would you do if you are in XYZ situation, how would you respond?) Tell me a time when you were in a difficult situation at work, how did you rectify the issue?

Data Analyst In Washington, DC

Interviewed at FSA

3.7★

Dec 20, 2014

Many personality questions and situation based question (i.e. What would you do if you are in XYZ situation, how would you respond?) Tell me a time when you were in a difficult situation at work, how did you rectify the issue?

There are 25 horses, and you want to rank the fastest 3 horses out of those 25. In each race, only 5 horses can run at the same time because there are only 5 tracks. What is the minimum number of races required to find the 3 fastest horses without using a stopwatch?

Data Analyst

Interviewed at Wix

4.1★

Jan 14, 2016

There are 25 horses, and you want to rank the fastest 3 horses out of those 25. In each race, only 5 horses can run at the same time because there are only 5 tracks. What is the minimum number of races required to find the 3 fastest horses without using a stopwatch?

Pick up a coin C1 given C1+C2 with probability of trials p(h1)=.7, p(h2)=.6 and doing 10 trials. And what is the probability that the given coin you picked is C1 given you have 7 heads and 3 tails?

Data Scientist

Interviewed at Meta

3.6★

Feb 25, 2015

Pick up a coin C1 given C1+C2 with probability of trials p(h1)=.7, p(h2)=.6 and doing 10 trials. And what is the probability that the given coin you picked is C1 given you have 7 heads and 3 tails?

Given two binary strings, write a function that adds them. You are not allowed to use any built in string to int conversions or parsing tools. E.g. Given "100" and "111" you should return "1011". What is the time and space complexity of your algorithm?

Data Scientist, Analytics

Interviewed at Meta

3.6★

Mar 6, 2015

Given two binary strings, write a function that adds them. You are not allowed to use any built in string to int conversions or parsing tools. E.g. Given "100" and "111" you should return "1011". What is the time and space complexity of your algorithm?

# Question 3: # Complete a function that returns a list containing all the mismatched words (case sensitive) between two given input strings # For example: # - string 1 : "Firstly this is the first string" # - string 2 : "Next is the second string" # # - output : ['Firstly', 'this', 'first', 'Next', 'second']

Data Engineer

Interviewed at Meta

3.6★

Jun 8, 2020

# Question 3: # Complete a function that returns a list containing all the mismatched words (case sensitive) between two given input strings # For example: # - string 1 : "Firstly this is the first string" # - string 2 : "Next is the second string" # # - output : ['Firstly', 'this', 'first', 'Next', 'second']

Tell me about your dream job

Data Analytics

Interviewed at BPO+

3.3★

Sep 24, 2019

Tell me about your dream job

You have a table with appID, eventID, and timestamp. eventID is either 'click' or 'impression'. Calculate the click through rate. Now do it in for each app.

Data Scientist

Interviewed at Meta

3.6★

Oct 23, 2017

You have a table with appID, eventID, and timestamp. eventID is either 'click' or 'impression'. Calculate the click through rate. Now do it in for each app.

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