**Explain DIMENSION REDUCTION:** Also, dimensionality reduction. “We can use a technique called principal component analysis to extract one or more dimensions that capture as much of the variation in the data as possible... Dimensionality reduction is mostly useful when your data set has a large number of dimensions and you want to find a small subset that captures most of the variation.”[grus] Linear algebra can be involved; “broadly speaking, linear algebra is about translating something residing in an m-dimensional space into a corresponding shape in an n-dimensional space.”[shin] See also linear algebra.

Different definitions in web development like **dimension reduction** in Dictionary D.

- Manual Data Mining:
- Meaning of computers to analyze large data sets to look for patterns that let people make business decisions. While this sounds like much of what data science is about, popular use of the term is much older dimension reduction.
- Manual Discrete Variable:
- Meaning potential values must be one of a specific number of values. If someone rates a movie with between one and five stars, with no partial stars allowed, the rating is a discrete variable. In a graph dimension reduction.
- Manual Data Science:
- Meaning extract knowledge and insights from large and complex data sets.”[patil] Data science work often requires knowledge of both statistics and software engineering. See also data engineer, machine dimension reduction.
- Manual Data Engineer:
- Meaning data wrangling. “Data engineers are the ones that take the messy data... and build the infrastructure for real, tangible analysis. They run ETL software, marry data sets, enrich and clean all that dimension reduction.
- Manual Dependent Variable:
- Meaning dependent value “depends” on the value of the independent variable. If you're measuring the effect of different sizes of an advertising budget on total sales, then the advertising budget figure dimension reduction.