Stocks slumped to fresh session lows Friday afternoon amid another steep drop in oil prices and mixed economic reports. The Nasdaq tumbled 2% and is now below its 50-day and 200-day moving averages, as well as the psychological 5,000 level. Meanwhile, the S&P 500 and the Dow Jones industrial average shed 1.8% and 1.7%, respectively. All 30 Dow stocks were lower.