10+ NCDEX Interview Questions and Answers

Query to find second largest salary of an employee.

• Use ORDER BY and LIMIT to sort and select the second highest salary.

• Assuming table name as 'employees' and salary column name as 'salary'.

• SELECT salary FROM employees ORDER BY salary DESC LIMIT 1,1;

There are three types of machine learning: supervised, unsupervised, and reinforcement learning.

• Supervised learning involves training a model on labeled data to make predictions on new data. Example: predicting house prices based on features like location, size, etc.

• Unsupervised learning involves finding patterns in unlabeled data. Example: clustering customers based on their purchasing behavior.

• Reinforcement learning involves training a model to make decisions based on rewar...read more

Feature selection is the process of selecting relevant features from a dataset, while feature engineering involves creating new features.

• Feature selection helps to reduce the dimensionality of the dataset and improve model performance.

• Feature engineering involves transforming or combining existing features to create new ones that may be more informative.

• Examples of feature engineering include creating interaction terms, scaling features, and encoding categorical variables.

• Bot...read more

Gradient Descent is an optimization algorithm used to minimize the cost function of a machine learning model.

• Gradient Descent is used in machine learning to find the optimal parameters of a model by minimizing the cost function

• It works by iteratively adjusting the parameters in the direction of steepest descent of the cost function

• There are two types of Gradient Descent: Batch Gradient Descent and Stochastic Gradient Descent

• Batch Gradient Descent updates the parameters after ...read more

Abstract class can have implementation while interface cannot. A class can implement multiple interfaces but can only inherit from one abstract class.

• Abstract class can have constructors while interface cannot.

• Abstract class can have non-abstract methods while interface can only have abstract methods.

• Abstract class can have instance variables while interface cannot.

• A class implementing an interface must implement all its methods while a class inheriting from an abstract class...read more

Linear regression is used for continuous data while logistic regression is used for categorical data.

• Linear regression predicts a continuous outcome while logistic regression predicts a probability of an event occurring.

• Linear regression uses a straight line to fit the data while logistic regression uses an S-shaped curve.

• Linear regression is used for predicting values like house prices while logistic regression is used for predicting binary outcomes like whether a customer w...read more

Joins in SQL are used to combine data from two or more tables based on a related column between them.

• Joins are used to retrieve data from multiple tables in a single query.

• There are different types of joins such as INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN.

• The columns used to join the tables must have the same data type and name.

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column;

BFS and DFS are traversal algorithms used in graphs and trees.

• BFS stands for Breadth First Search and explores the graph level by level.

• DFS stands for Depth First Search and explores the graph by going as deep as possible before backtracking.

• BFS uses a queue data structure while DFS uses a stack or recursion.

• BFS is useful for finding the shortest path while DFS is useful for finding all possible paths or cycles.

• BFS has a higher memory requirement than DFS.

• Example: BFS can be ...read more

Measures of Dispersion are used to describe the spread of data around the central tendency.

• Measures of Dispersion include Range, Variance, Standard Deviation, and Interquartile Range.

• Range is the difference between the maximum and minimum values in a dataset.

• Variance measures how far each value is from the mean.

• Standard Deviation is the square root of the variance.

• Interquartile Range is the difference between the 75th and 25th percentiles.

Experience with various AWS services like SQS, S3, CloudFront, RDS, Aurora, and Lambda.

• Experience setting up and managing SQS for message queuing

• Experience using S3 for scalable storage solutions

• Experience configuring CloudFront for content delivery

• Experience working with RDS and Aurora for database management

• Experience developing serverless applications with Lambda functions

Lazy loading in Angular is a technique where modules are loaded only when they are needed, improving performance by reducing initial load time.

• Lazy loading helps in loading only the required modules when navigating to a specific route.

• It improves the initial load time of the application by loading modules asynchronously.

• Lazy loading is achieved by using the loadChildren property in the route configuration.

• Example: loadChildren: () => import('./lazy-loaded-module').then(m => m...read more

Different types of attributes in STEP include simple attributes, complex attributes, and reference attributes.

• Simple attributes: Basic data types like text, number, date, etc.

• Complex attributes: Attributes composed of multiple simple attributes.

• Reference attributes: Attributes that reference other entities or objects.

• Example: Simple attribute - Product Name, Complex attribute - Address (composed of street, city, state, zip), Reference attribute - Customer ID (referencing a cu...read more