2:10 mark he states J->F is a sufficient condition yet he refers to the word "must" in the text. The previous courses show "must" is a necessary condition. Meaning, the correct way to show this should be F->J. BUT, this doesn't make sense in this context. Please advise

To confirm, group 1 sufficient indicators go to the left of the arrow, but group 2 necessary conditions go to the right of the arrow?