Hey there
That is actually a cool assignment, when i was in year 12, last year, our teacher kept us away from the curator/exhibition type questions, but they sound easy/fun.
In simple terms, a curator is the person within an art gallery (thus within an exhibition) that selects art works for a particular gallery/exhibition. Obviously, a specific exhibiton like the one in your question has a specialised theme, unlike maybe a large gallery e.g. AGNSW. If I was you, out of interest, I would have a poke around at the AGNSW website and have a browse at what Edmund Capon (hopefully correct spelling) says on the site and find whatever you can - he is the curator of a pretty important gallery. Out of curiosity, what artists/works are you selecting for your assignment? What defines modernity for you?
Sorry, being at uni now, doing a degree as far from art/creative arts as possible means art deprivation - and u've got my 'art juices' flowing again. Theory is fantastic.
Peace.
P.S. Whoops, misread your question. You wanted to know what a curator statement is, opposed to a curator - sorry!