Consider the following three statements: as children grow older, their weight increases. as children grow older, they expand their vocabulary. as children's weight increases, their vocabulary expands. does statement #3 describe a correlational relationship? a causal relationship? explain your answer.

This would be a correlational relationship.
Correlational relationship means the occurances can occur at the same time...they might be associated but one does not cause the other.
Casual relationship is basically a cause/effect relationship...one event occurs because of the other.

Just because a childs weight increases, does not mean their vocabulary expands...there are skinny people with great vocabulary. However, that does not mean that a " chubby " person cannot have good vocabulary. 

J= r + 9 because since jessica rode 9 more miles than roger, you add 9 miles to rogers mileage.