CES Information Technologies Lead Data Analyst Interview Questions and Answers

Q1. What is Overfitting in decision tree
Ans. 
Overfitting in decision trees occurs when the model learns noise in the training data rather than the underlying pattern.
• Overfitting happens when the decision tree is too complex and captures noise in the training data.

• It leads to poor generalization on unseen data, as the model is too specific to the training set.

• To prevent overfitting, techniques like pruning, setting a minimum number of samples per leaf, or using en
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Q2. What is bagging
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Bagging is a machine learning ensemble technique where multiple models are trained on different subsets of the training data and their predictions are combined.
• Bagging stands for Bootstrap Aggregating.

• It helps reduce overfitting by combining the predictions of multiple models.

• Random Forest is a popular algorithm that uses bagging by training multiple decision trees on random subsets of the data.
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Q3. What is neuron How its used in DL
Ans. 
A neuron is a basic unit of a neural network that receives input, processes it, and produces an output.
• Neurons are inspired by biological neurons in the human brain.

• They receive input signals, apply weights to them, sum them up, and pass the result through an activation function.

• Neurons are organized in layers in a neural network, with each layer performing specific tasks.

• In deep learning, multiple layers of neurons ar...read more
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It was having basic aptitude questions

Q1. They asked basic english question
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Q2. And alos topic was provided so we had to speak on it.
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Q1. SQL syntax and difference between having and where clause
Ans. 
HAVING clause is used with GROUP BY to filter grouped rows, WHERE clause is used to filter individual rows.
• HAVING clause is used with GROUP BY to filter grouped rows based on aggregate functions

• WHERE clause is used to filter individual rows based on conditions

• HAVING clause is applied after GROUP BY, WHERE clause is applied before GROUP BY

• HAVING clause can only be used with SELECT statement that contains a GROUP BY clau
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Q2. Difference between array and linkedlist,stack and queue
Ans. 
Arrays store elements in contiguous memory, while linked lists use nodes with pointers. Stacks follow LIFO, queues follow FIFO.
• Arrays store elements in contiguous memory locations, allowing for constant time access to elements using indices.

• Linked lists use nodes with pointers to the next node, allowing for dynamic memory allocation and insertion/deletion at any position.

• Stacks follow Last In First Out (LIFO) principle...read more
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Q1. Tell me about your self
Ans. 
I am a data science enthusiast with a strong background in statistics and machine learning.
• Completed coursework in data analysis, statistical modeling, and predictive analytics

• Proficient in programming languages such as Python, R, and SQL

• Experience with data visualization tools like Tableau and Power BI

• Worked on projects involving regression analysis, clustering, and classification algorithms
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Q2. Why you want to join this role
Ans. 
I am passionate about using data to solve complex problems and make informed decisions.
• I have a strong background in statistics, mathematics, and programming, which are essential skills for a data science role.

• I am excited about the opportunity to work with real-world data and apply machine learning algorithms to extract valuable insights.

• I am eager to learn from experienced data scientists and contribute to innovative
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Basic test with Data Structures, algorithms, SQL questions

Q1. Questions about basic ML Algorithms
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Q1. Questions about SQL
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Q2. Questions about python dataframes
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Q3. Difference between random forest and decision tree
Ans. 
Random forest is an ensemble learning method using multiple decision trees to improve accuracy and reduce overfitting.
• Random forest uses multiple decision trees to make predictions.

• Decision tree is a single tree structure used for classification and regression.

• Random forest reduces overfitting by averaging the predictions of multiple trees.

• Decision tree can be prone to overfitting if not pruned properly.

• Random forest i...read more
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Verbal reasoning is a type of aptitude test that assesses your ability to understand,analyze,and interpret written information.

Q1. TELL ME ABOUT YOURSELF
Ans. 
I am a data science enthusiast with a strong background in statistics and machine learning.
• Completed coursework in data analysis, statistical modeling, and predictive analytics

• Proficient in programming languages such as Python, R, and SQL

• Experience with data visualization tools like Tableau and Power BI

• Completed projects involving regression analysis, clustering, and classification algorithms
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Q2. TELL ME ABOUT PROJECT
Ans. 
Developed a machine learning model to predict customer churn for a telecom company.
• Used Python and scikit-learn for data preprocessing and model building

• Performed feature engineering to create new variables for the model

• Evaluated model performance using metrics like accuracy, precision, and recall
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Q3. About skills and how did u learn them
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Q4. Why do u want to work with us
Ans. 
I am passionate about data science and believe in the impact it can have on driving insights and decision-making.
• I am excited about the opportunity to work with a team of experienced data scientists and learn from their expertise.

• I am impressed by the innovative projects and cutting-edge technologies that your company is involved in.

• I am eager to apply my skills and knowledge in data science to real-world problems and
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Q5. How do you stay clam when talking to difficult people
Ans. 
I remain calm by actively listening, staying patient, and focusing on finding common ground.
• Practice active listening to understand their perspective

• Stay patient and avoid reacting emotionally

• Focus on finding common ground or a solution to the issue

• Use positive body language and tone of voice to convey understanding and empathy
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Basic statistics questions and coding questions on modeling

Q1. Discussion was mainly on the project I have worked on
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Q1. Project discussion 2 case studies Questions on sensitivity analysis Precision recall with non binary data
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Q1. How would you solve conflicts between two people in your team? Why are you leaving your company?
Ans. 
To solve conflicts between two people in my team, I would encourage open communication, facilitate a discussion, and find a mutually agreeable solution.
• Encourage open and honest communication between the two individuals involved

• Facilitate a discussion where both parties can express their concerns and perspectives

• Identify common ground and areas of agreement

• Encourage empathy and understanding towards each other's viewpo...read more
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Q1. 1.Difference between loc and iloc in pandas. SQL queries 2.Pivot the table. 3.find the cummaltive sum of orders till the current day. Scenario based questions like - How will you address decline in revenu...read more
Ans. 
loc and iloc are two methods in pandas used for selecting data from a DataFrame based on labels or integer index.
• loc is label-based, meaning you specify the row and column labels to select data

• iloc is integer index-based, meaning you specify the row and column indices to select data

• Example: df.loc['row_label', 'column_label'] vs df.iloc[row_index, column_index]
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Q1. Asked about scenario-based Small case study questions
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Q2. Explain statistical concepts like Hypothesis testing, and type 1 and type 2 errors.
Ans. 
Hypothesis testing is a statistical method to test a claim about a population parameter. Type 1 error is rejecting a true null hypothesis, and type 2 error is failing to reject a false null hypothesis.
• Hypothesis testing involves formulating a null hypothesis and an alternative hypothesis.

• Type 1 error occurs when we reject a null hypothesis that is actually true.

• Type 2 error occurs when we fail to reject a null hypothes...read more
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Q3. Coding questions about Python and SQL
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Q4. Questions about Machine learning algorithms, AUC ROC, Classification metrics
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Q1. Explain about projects working on.
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Q2. About a small scenario-based case study, how will you perform
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Q3. How will you handle angry clients
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Q1. Situation-based questions, small management scenario, what you will do
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Q2. More questions about you? what you like and how the organization is good for you
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