I've never heard of a 'concrete statement', but I'd guess it's a statement about a concrete noun. Less concrete would be figurative speech about a concrete noun. Even less concrete would be an abstract noun. Even less concrete would be figurative speech about an abstract noun:
This is a raindrop. > This raindrop is the size of a pebble. > I think I can hear bad weather on the way....
You could even have a hierarchy of figurative speech: Metaphor using concrete image > Metaphor using abstract image > simile using concrete image > simile using abstract image
These are just some ideas. Try them out on your test sentences, and post your answers here.