$.$ An anthropologist is interested in the $($linear$)$ relationship between body length and head volume among remains

found at an excavation sight. She does not feel that changes in one variable $$cause$$ changes in the other, but does

believe that there will be a positive linear relationship between the two. Her appropriate null and alternative hypotheses

would be $($Choose one$)$:

a$)$ H$0$: b $=0$ HA: b $>0$

b$)$ H$0$: r $=0$ HA: r $>0$

c$)$ H$0$: E $=0$ HA: E $>0$

d$)$ H$0$: U $=0$ HA: U $>$