According to your text, the IQ scores of immigrants in the early 20th century reflected the length of time they have lived in the United States, rather than their true intelligence. In the language of research methodology, length of time in the United States is a(n) __________ variable in this instance.

A) confounding
B) independent
C) control
D) IQ and socioeconomic status are unrelated.

Confounding Variable

A variable other than the independent variable that may cause a result or effect in an experiment, making it difficult to isolate the impact of the independent variable.

Length of Time

A measurement that quantifies the continuous period during which an action, process, or condition exists or persists.

IQ Scores

Standardized measures used to assess human intelligence relative to a statistical normal distribution.