Final answer:
The quote, "Raven's Progressive Matrices is probably the best measure of a general intelligence factor," is attributed to Arthur Jensen, an educational psychologist known for his research on intelligence. Jensen proposed the existence of Level I and Level II abilities that contribute to intelligence. It is important to note that his views on race and intelligence have faced considerable controversy.
Step-by-step explanation:
The quote, "Raven's Progressive Matrices is probably the best measure of a general intelligence factor," is often attributed to the educational psychologist Arthur Jensen.
Jensen conducted extensive research on intelligence, particularly with regards to IQ testing.
He argued that intelligence is influenced by genetics and proposed the existence of Level I and Level II abilities.
However, it should be noted that Jensen's views on race and intelligence have been highly controversial and criticized.