Outlier
An outlier is a data point that differs significantly from other observations and may indicate error or genuine variation. Data+ covers identifying and handling outliers during preparation and analysis.
All DA0-002 Terms
ETL
ETL (Extract, Transform, Load) is a data-integration pattern that extracts data from sources, transforms it, then loads it into a target store.
ELT
ELT (Extract, Load, Transform) loads raw data into the target system first and transforms it there, often used with cloud data warehouses and lakes.
Data warehouse
A data warehouse is a central repository optimized for analytical querying (OLAP) of integrated, structured data.
Data lake
A data lake is a storage repository that holds large volumes of raw data in native formats — structured, semi-structured, and unstructured — until needed.
OLAP
OLAP (Online Analytical Processing) is a class of systems optimized for complex analytical queries and aggregations over large datasets.
OLTP
OLTP (Online Transaction Processing) is a class of systems optimized for high volumes of short, transactional read/write operations.
Data cleaning
Data cleaning is the process of detecting and correcting errors — missing values, duplicates, outliers, and inconsistencies — to improve data quality.
Data profiling
Data profiling is the examination of data to summarize its structure, content, and quality before analysis.
Outlier
An outlier is a data point that differs significantly from other observations and may indicate error or genuine variation.
Descriptive statistics
Descriptive statistics summarize a dataset using measures of central tendency (mean, median, mode) and dispersion (range, variance, standard deviation).
Regression
Regression is a statistical method that models the relationship between a dependent variable and one or more independent variables.
Correlation
Correlation measures the strength and direction of the linear relationship between two variables, without implying causation.
Hypothesis testing
Hypothesis testing is a statistical procedure that uses sample data to evaluate a claim about a population, assessing significance with a p-value.
Data governance
Data governance is the framework of policies, ownership, stewardship, and standards that ensures data is accurate, secure, and used appropriately.
PII
PII (Personally Identifiable Information) is data that can identify an individual and is subject to privacy regulations and protection controls.