Wall Street inched lower on Tuesday as investors stayed away from big bets before on outcome of the Federal Reserve policy meeting suggesting whether the central bank curbs its stimulus measures. The Standard & Poor's 500 Index slipped 0.31% and closed at 1,781, the Dow Jones industrial average fell 0.06% to 15,875.26 and the Nasdaq Composite Index closed at 4,023.68, 0.14% lower.