Amazon Data Scientist Interview Questions & Process

Amazon is the world’s largest multinational company that focuses on e-commerce, cloud computing, artificial intelligence, and digital streaming. It has grown significantly, and the prime reason for the spectacular rise is its innovative technology and professional scientists and engineers. They hire many data scientists and are known as one of the best among the top companies for a data scientist. Amazon offers both handsome pays with Great career opportunities. Let us know Amazon Data Scientist Interview Questions & Process.

Amazon Data Scientist Interview Questions & Process

If you are motivated to work for Amazon do read this article. I am penning down all the skills interview questions and process. It would help you in preparation for an interview at Amazon. The data sourced from various websites it would give you complete information. 

Amazon Data Scientist

Here we will cover a complete guide on Amazon’s Data Scientists

We will cover:

  1. Brief about what is Data Scientist?
  2. The Data Scientist interview process 
  3. What questions does Data Scientist go through in the Amazon interview?
  4. Tips and tricks to clear interview at Amazon

Brief description of a Data Scientist

Data scientists are data wranglers, gatherers, and analysers. A set of structured and unstructured data are gathered and analyzed by them. Today, organizations and businesses collect millions of data every day. It is the reason why a career as a data scientist is highly in demand. They spend their working hours doing data mining and traditional technical duty such as cleaning, compiling, and presenting data for the organization.

Jeff Bezos Career Advice
Jeff Bezos Career Advice

As we know, Amazon is known as one of the best tech companies, so most the data scientist wants to get hired. There are several job posts as an Amazon data scientist, and it is going in high demand. 

Working at Amazon as a Data Scientist

Working at Amazon as a data scientist is a tough challenge as the first barrier is the interview questions process. Once you break, you could earn the position in Amazon. Look no further because, in this article, you will find various types of questions asked during the interview process in past years at Amazon. Amazon is a mixture of different factors such as diversity, Equity, and Inclusion. It made it different from others. At Amazon, these factors make a positive impact on the Data scientist to work for it.

The interview process 

As mentioned above, the interview process for data scientists is challenging, and the candidates go through a series of interviews. But the interview process at Amazon is similar to other tech companies such as Google, Microsoft, Apple, Facebook, and so on. 

Here I am going to discuss the series of interviews. 

a) Phone screening: 

The first step that candidates go through is an initial phone interview. The hiring manager or recruiter usually conducts this interview. This first round is to check the stability and resume of the candidate for the job position. In this round, the applicants go through are general HR questions. The HR manager asks questions such as 

  • Do you have working experience in a tech company? 
  • Why do you select Amazon, and why do you want to work here?
  • Why would we hire you? 
  • What all programming languages do you know?

B) The Technical Screening: The second stage of the interview is the technical screening round. In this round, the candidates also go through technical questions such as 

  • Explain the bias-variance trade-off?
  • What is Bayes theorem?
  • Makes to solve questions of C++, SQL, etc. 
  • HR makes the candidate do coding.

The HR team does properly detailed checking of the steps and calculations used in the question and coding.  

Let us see some technical questions given to solve at the Amazon interview. 

Q)  Solve this program: In the table, the end date of one project matches the start date of another project.

 The projected table provided:

COLUMN TYPE

  ID

Integer

  title

String

  start date

date time

  End date

date time

  budget

float

Q) Solve this table problem: 

Table A: Contains one million records with ID and AGE fields. 

Table B: Contains hundreds of records with two fields as well, ID and SALARY. 

Let us assume Table B has a mean salary of 50K and a median salary of 100K. 

SELECT A.ID, A.AGE, B.SALARY

FROM A

LEFT JOIN B

ON A.ID = B.ID

WHERE B.SALARY > 50000

-Give the query above gets run, about how many records would return?

The candidate also go through questions related to machine learning, such as

  • Briefly describe PCA?
  • What are the different types of the algorithm in Machine learning?
  • What is a decision tree?
  • How would you use the F1 score? 

c) Onsite interview: Once the applicants successfully pass the technical interview, they are now applicable for an onsite Interview. In this interview, the interviewer observes the leadership quality of the candidate. It is a direct interview in which the interviewer judge candidates based on everything.  

It is a long process with back-to-back 5 or 6 stages of interview and lasts for approx. 6 hours. 

The list given below will show how the interview process looks like:

  A behavioral test: This test is conducted by the HR team on the candidate based on behaviour and personality to access the cultural fit. 

  Onsite technical check: It involves the direct interview of AB testing and data analysis

  SQL-based interview: This stage of the interview is basically about the testing of the SQL programming language. This test is categorized into seven parts. 

  • Definition of SQL questions 
  • Metrics of SQL questions 
  • Analytics SQL questions
  • ETL SQL questions
  • Database Design questions
  • SQL questions ( logical based) 

  Algorithms and optimization: This stage consist of a Python-based interview. Here interviewer conducts a deep conversation and testing of the candidates upon Python. Probability-related questions. The test has five parts: 

  • Statistics and distribution related questions
  • Questions based on matrices and NumPy functions 
  • Questions based on string parsing and data manipulation
  • Questions based on Pandas data munging

  Modeling case study and machine learning interview: There are three main types of case studies that candidates go through at Amazon. This stage is to observe and examine how promptly candidates can approach the situation, communicates their findings, and work accordingly. 

  • Business case studies
  • Product case studies
  • Prediction/ Modelling case studies

Common interview questions with their examples at Amazon for a Data Scientist

Amazon consists of different departments and teams. Candidates applying to these departments go through advanced interview questions and process related to the amazon data scientist field. 

In this article, you will go through questions asked in the Amazon. 

1- Gives to write small programs with a small string and large strings. (USING JAVA)

Solution

class SmallString{

    public static void main(String[] args) {

        String smallString = “this is a small String.”;

        String capitalString = “THIS IS A CAPITAL STRING.”;

        System.out.println (smallString + capitalString);

    }

}

Output

It is a small String. IT IS A CAPITAL STRING.

2-  Differentiate between Lasso and Ridge Regression.

A-  Lasso regression: 

  • Lasso regression is the sum of the coefficient. 
  • Rigid regression is a sum of the square of residuals.

The difference between the lasso and ridge regression is:

 Lasso tends to make coefficient absolute zero, whereas Ridge never sets the value of coefficient to absolute zero. 

3- How will you modify the table which contains billions of rows?

Solution: 

Any inputs will be helpful.

DECLARE @notNULLRecordsCount INT; 

SET @notNULLRecordsCount = 1;

WHILE @notNULLRecordsCount > 0 

  BEGIN 

  BEGIN TRANSACTION;

 UPDATE TOP (100000)

dbo.BillionRowsTable

    SET Column1 = NULL,

       Column2 = NULL,

       Column3 = NULL  

WHERE Column1 IS NOT NULL OR Column2 IS NOT NULL OR Column3 IS NOT NULL;

SET @notNULLRecordsCount = @@ROWCOUNT;

COMMIT TRANSACTION;

END

5- Concatenate two tuples 

    tup1= (1,”a”, True)

    tup2: (4, 5, 6)

Solution:

Code

tup1=(1,”a”,True)

tup2=(4,5,6)

tup1+tup2

Output

(1, ‘a’, True, 4, 5, 6)

All you have to do is, use the ‘+’ operator between the two tuples, and You will get the concatenated result.

Code

tup1=(1,”a”,True)

tup2=(4,5,6)

tup2+tup1

Output

Tup2+tup1

(4, 5, 6, 1, ‘a’, True) 

6- What is the SVM algorithm (briefly with diagram?)

A- A support vector machine that supervises a machine learning algorithm uses it for regression and classification. 

7-Initialize a 5*5 numpy array (Use only .zeros () method)

Solution:

Import numpy as np

N1=np.zeros ((5, 5))

N1

Using np.zeros (), now pass it inside the dimension. 

We will pass (5, 5) inside the .zeros () method because we want a 5*5 matrix.

Output

Array ([[0, 0, 0, 0, 0.],

          [0, 0, 0, 0, 0.],

          [0, 0, 0, 0, 0.],

          [0, 0, 0, 0, 0.],

          [0, 0, 0, 0, 0.]])

8- Explain what is overfitting?

Overfitting is a statistical model that works against the training data. It may fail to fit the additional data, resulting in high variance and low bias. 

Graph

9- Mention any two features of Python?

  • Python is the language for debugging. 
  • Python is an object-oriented language. It supports the concept of classes. 

10- What P-value is? 

A- A measure of the probability is known as P-value. It observes the difference between things just by random chance. 

It is calculated by using a formula: 

P-value = P (TS ts | H 0 is true) = cdf (ts)

Tips and tricks

  • Remember to brush on all the questions based on an algorithm, machine learning, and optimizing queries.
  • Must read about all the fourteen leadership principles before going to the interview. 
  • Practice all the three cases questions. 
  • Brush up all the questions related to all the programming languages. 
Concluding

As Amazon is the most renowned company in the world, it is also best for working. Working in such as large company as a Amazon has its benefits and requirements. Their interview process is also challenging, so its preparation must also be up to date and proportional. In the preparation of a data Scientist interview questions process at Amazon, this article may guide and help you. 

Amazon Data Scientist Interview Questions & Process

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