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.
Which statistical test is used to determine if there's a significant difference between the means of two independent groups?
- Chi-squared test
- T-test (independent samples)
- ANOVA (Analysis of Variance)
- Correlation test
The T-test for independent samples is used to determine if there is a significant difference between the means of two independent groups. It is commonly employed in hypothesis testing to compare means. The chi-squared test is used for testing the independence of categorical variables, ANOVA for comparing more than two group means, and the correlation test for measuring the strength and direction of a linear relationship.
In CNNs, the _______ layer is used to detect local features such as edges and textures.
- Convolutional
- Pooling
- Recurrent
- Fully Connected
The Convolutional layer in Convolutional Neural Networks (CNNs) is responsible for detecting local features in the input data, such as edges and textures. It does this by applying convolution operations across the input data, which allows the network to recognize spatial patterns in images or other structured data.
Which approach in recommender systems involves recommending items by finding users who are similar to the target user?
- Collaborative Filtering
- Content-Based Filtering
- Hybrid Filtering
- Matrix Factorization
Collaborative Filtering is a recommendation approach that identifies users similar to the target user based on their interactions and recommends items liked by those similar users. It relies on user-user similarity for recommendations.
Which algorithm is commonly used for predicting a continuous target variable?
- Decision Trees
- K-Means Clustering
- Linear Regression
- Naive Bayes Classification
Linear Regression is a commonly used algorithm for predicting continuous target variables. It establishes a linear relationship between the input features and the target variable, making it suitable for tasks like price prediction or trend analysis in Data Science.
In a data warehouse, the _________ table is used to store aggregated data at multiple levels of granularity.
- Fact
- Dimension
- Staging
- Aggregate
In a data warehouse, the "Fact" table is used to store aggregated data at various levels of granularity. These tables contain measures or metrics, which are essential for analytical queries and business intelligence reporting.
In a Hadoop ecosystem, which tool is primarily used for data ingestion from various sources?
- HBase
- Hive
- Flume
- Pig
Apache Flume is primarily used in the Hadoop ecosystem for data ingestion from various sources. It is a distributed, reliable, and available system for efficiently collecting, aggregating, and moving large amounts of data to Hadoop's storage or other processing components. Flume is essential for handling data ingestion pipelines in Hadoop environments.
In which scenario would Min-Max normalization be a less ideal choice for data scaling?
- When outliers are present
- When the data has a normal distribution
- When the data will be used for regression analysis
- When interpretability of features is crucial
Min-Max normalization can be sensitive to outliers. If outliers are present in the data, this scaling method can compress the majority of data points into a narrow range, making it less suitable for preserving the information in the presence of outliers. In scenarios where outliers are a concern, alternative scaling methods like Robust Scaling may be preferred.