Peter Cardillo, chief market economist at Rockwell Global Capital, weighs in on whether Wall Street is heading towards a major correction after the Dow fell over 200 points in afternoon trading on Friday as investor's fear grows over emerging markets. The Dow Jones industrial average tumbled 248.43 points, or 1.53 percent, to 15.948.92. The S&P 500 lost 30.24 points, or 1.66 percent, to 1,798.09. The Nasdaq Composite dropped 77.93 points, or 1.85 percent, to 4,140.94.