Research on IQ Differences Between African American and Caucasian Students

Multiple Choice

Research on IQ differences between African American and Caucasian students indicates that:

A) the difference between mean IQ scores has been shrinking during the past 25 years.
B) the difference between mean IQ scores has been increasing during the past 25 years.
C) it is impossible to compare changes in IQ score between the two ethnic groups because the IQ tests have changed so much during that time.
D) the difference between mean IQ scores has remained unchanged during the past 25 years.