Stocks ended mixed Friday amid mixed economic data and one high-profile dive, while options expiration sent Big Board volume through the roof. The Nasdaq fell 0.2% and the S&P 500 ceded a scant 0.1%. But the Dow Jones industrial average added a wee bit . Volume dipped 4% on the Nasdaq but soared 47% on the NYSE, according to preliminary data. The University of Michigan Consumer Confidence Index climbed 2.5 points to 76.3 from January's 73.8. That's