An investigation fi nds a positive correlation between IQ scores and length of attention span among 10-year-olds

An investigation fi nds a positive correlation between IQ scores and length of attention span among 10-year-olds. From this fi nding, which of the following would be a reasonable conclusion?

a. A long attention span is a cause of intelligence.

b. A high IQ is a cause of long attention span.

c. There is a high probability that a large sample of high-IQ 10-year-olds will have a shorter mean attention span than a large sample of low-IQ 10-year-olds.

d. One would predict longer attention spans for high-IQ 10-year-olds than for low-IQ 10-year-olds