Yes, STATEMENT is a Scrabble word!

Letter values in Scrabble US: S 1, T 1, A 1, T 1, E 1, M 3, E 1, N 1, T 1.

Is it a valid word?

STATEMENT is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a message that is stated or declared; a communication (oral or written) setting forth particulars or facts etc
a fact or assertion offered as evidence that something is true
(music) the presentation of a musical theme
a nonverbal message
the act of affirming or asserting or stating something
(computer science) a line of code written as part of a computer program
a document showing credits and debits

Also: program line, financial statement.