Variance shared by two or more variables.

• A. Communality
• B. Component matrix
• C. Common variance
• D. Confidence interval

Answer: (C)

In factor analysis, you split each variable’s variance into what is shared with other variables (common variance) and what is unique to that variable. The quantity that represents the variance shared by two or more variables—due to underlying factors—is called common variance. Communality is closely related: it’s the part of a single variable’s variance that is accounted for by the common factors, often shown as a per-variable value. So the overall shared variance across variables is best described as common variance. The other options refer to different ideas (confidence intervals for estimates, and the component matrix related to loadings), not the shared variance across variables.