Raw logs from web servers often contain unstructured data, as they can consist of a mix of text, images, and various file types that lack a specific format. Unstructured data is not organized in a traditional tabular structure.

In complex ETL (Extract, Transform, Load) processes, "Data lineage" is crucial for ensuring data quality and accuracy. Data lineage helps track the origin and transformation of data, ensuring that the data remains reliable and traceable throughout the pipeline.

AUC-ROC stands for Area Under the Receiver Operating Characteristic curve. The ROC curve is a graphical representation of a model's performance, particularly its ability to distinguish between the positive and negative classes. AUC (Area Under the Curve) quantifies the overall performance of the model, with higher AUC values indicating better discrimination.

Fine-tuning in transfer learning involves taking a pre-trained model's architecture and training it with new data, adjusting the model's parameters to suit the specific task. It's a common technique for leveraging pre-trained models for custom tasks.

In this scenario, you would use a content-based recommendation approach. It recommends items (in this case, movies) based on their content or features, such as genre, actors, and plot. Collaborative filtering and hybrid systems focus on user behavior and preferences, while popularity-based recommendations don't consider movie content.

In a normal distribution, approximately 95% of the data falls within two standard deviations of the mean. This is a fundamental property of the normal distribution, as specified by the Empirical Rule or the 68-95-99.7 rule, which describes the percentage of data within one, two, and three standard deviations of the mean.

InfluxDB is specifically designed for time-series data, making it a suitable choice for applications that need to efficiently store and query time-stamped data, such as IoT or monitoring systems. Its structure and optimizations are tailored for this use case.

For real-time analysis on streaming data, Apache Spark is a powerful tool. It provides excellent performance capabilities and extensive libraries for stream processing, making it suitable for handling and analyzing large volumes of data in real-time.

Latent Semantic Analysis (LSA) is an NLP technique that transforms text into a meaningful vector space by capturing latent semantic relationships between words. It helps in reducing the dimensionality of text data while preserving its meaning. The other options are not methods for transforming text into numerical vectors and serve different purposes in NLP and data analysis.

One of the most popular algorithms used in collaborative filtering for recommender systems is Singular Value Decomposition (SVD). SVD is a matrix factorization technique that can be used to make recommendations based on user-item interactions.