What term describes the portion of a variable's variance that is unique and not shared with other variables?

What term describes the portion of a variable's variance that is unique and not shared with other variables?

• A. Unique variance
• B. Common variance
• C. Communality
• D. Covariance

Answer: (A)

Unique variance is the portion of a variable’s variance that is not shared with other variables. In factor analysis and related ideas, a variable’s total variance is split into what it shares with others (common variance, or communality) and what remains unique to that variable (unique or specific variance). The common/communality part is explained by underlying factors, while the unique variance remains unexplained by those shared factors. Covariance, on the other hand, measures how two variables vary together, not the portion of a single variable’s variance.

Unique variance is the portion of a variable’s variance that is not shared with other variables. In factor analysis and related ideas, a variable’s total variance is split into what it shares with others (common variance, or communality) and what remains unique to that variable (unique or specific variance). The common/communality part is explained by underlying factors, while the unique variance remains unexplained by those shared factors. Covariance, on the other hand, measures how two variables vary together, not the portion of a single variable’s variance.