How can I repair a wall with cracked paint?
If it was built in 1947, there's a decent chance there's lead paint there. That means you can't sand it. I would buy a lead testing kit to make sure (they're readily available online and in some stores. If it is, you'll need to take some precautions first or call a professional removal company.

Provided there's no lead, you might want to go with a no-shrink vinyl spackle instead of straight joint compound. I've found it cracks less. Sanding and spackling should do the trick. I'd go a primer route as well. Will give you better coating over the old paint.