Sorry, it doesn't really mean much as the state of your ceiling joists are what keeps your upstairs, upstairs!
Its an impossible question to answer as there could be woodworm, dry rot, or any number of things in the timber. Even if I seen a picture of a joist if wouldn't be good enough to give you an answer as I wouldn't be able to say if they were all like that or not. There's a lot of limiting factors I'm afraid.
Depending on where you live in the world, most 1930's houses were brick/block with the same on the internal walls so I'm guessing all walls downstairs are load bearing walls, am I correct?