Which data warehousing schema involves a central fact table and a set of dimension tables?

  • Snowflake Schema
  • Star Schema
  • Denormalized Schema
  • NoSQL Schema
The Star Schema is a common data warehousing schema where a central fact table stores quantitative data, and dimension tables provide context and details about the data. This schema simplifies querying and reporting.

You are working with a database that contains tables with customer details, purchase histories, and product information. However, there are also chunks of data that contain email communications with the customer. How would you categorize this database in terms of data type?

  • Structured data
  • Semi-structured data
  • Unstructured data
  • Big data
This database contains a mix of structured data (customer details, purchase histories, and product information) and semi-structured data (email communications). Semi-structured data is characterized by having some structure but also includes elements like emails, making it different from fully structured data.

The statistical test called _______ is used when we want to compare the means of more than two groups.

  • T-test
  • Chi-squared
  • ANOVA
  • Regression
Analysis of Variance (ANOVA) is a statistical test used when comparing the means of multiple groups. It assesses whether there are statistically significant differences between the group means, making option C the correct answer.

In NLP, which technique allows a model to pay different amounts of attention to different words when processing a sequence?

  • One-Hot Encoding
  • Word Embeddings
  • Attention Mechanism
  • Bag of Words (BoW)
The attention mechanism in NLP allows a model to pay different amounts of attention to different words when processing a sequence. This mechanism is a fundamental component of transformer-based models like BERT and GPT, enabling them to capture contextual information and understand word relationships in sentences, paragraphs, or documents.

What SQL command would you use to retrieve all the records from a table named "Employees"?

  • SELECT * FROM Employees
  • SHOW TABLE Employees
  • GET ALL Employees
  • FETCH Employees
To retrieve all the records from a table named "Employees" in a relational database like MySQL, you would use the SQL command: SELECT * FROM Employees. The SELECT * statement retrieves all columns and rows from the specified table, effectively fetching all the records.

What is the primary benefit of using ensemble methods in machine learning?

  • Improved generalization and robustness
  • Faster model training
  • Simplicity in model creation
  • Reduced need for data preprocessing
Ensemble methods in machine learning, such as bagging and boosting, aim to improve the generalization and robustness of models. They combine multiple models to reduce overfitting and improve predictive performance, making them a valuable tool for creating more accurate and reliable machine learning models.

In Cassandra, data retrieval is fast because it uses a _______ based data model.

  • Relational
  • Document-oriented
  • Columnar
  • Key-Value
Cassandra uses a columnar-based data model. This model allows for efficient data retrieval and storage, making it suitable for applications with high read and write workloads, such as time-series data or analytics.

The range of a dataset is calculated by taking the difference between the maximum and the _______ value.

  • Minimum
  • Median
  • Mean
  • Mode
The range of a dataset is calculated by subtracting the minimum value from the maximum value. This measures the spread of data from the smallest to the largest value, making option A the correct answer.

What is the main challenge addressed by the transformer architecture in NLP?

  • Handling sequential data effectively
  • Capturing long-range dependencies
  • Image classification
  • Speech recognition
The main challenge addressed by the transformer architecture is capturing long-range dependencies in sequential data. Transformers use self-attention mechanisms to understand the relationship between distant words in a sentence, making them effective for various NLP tasks like machine translation and text summarization.

Which type of data is typically stored in relational databases with defined rows and columns?

  • Unstructured data
  • Tabular data
  • Hierarchical data
  • NoSQL data store
Relational databases are designed for storing structured data with well-defined rows and columns. This structured format allows for efficient storage and querying of data. Unstructured data, on the other hand, lacks a predefined structure.