US STOCKS-Wall Street gains driven by surge in oil prices
* Oil prices jump about 5 pct
* Gap sinks after poor March same-store sales
* Indexes up: Dow 0.63 pct, S&P 0.68 pct, Nasdaq 0.50 pct (Adds details, changes comment, updates prices)
By Yashaswini Swamynathan and Abhiram Nandakumar
April 8 (Reuters) - A strong rebound in oil pushed U.S. stocks higher on Friday, while investors took comfort in Federal Reserve Chair Janet Yellen's positive comments on the economy.
Crude jumped more than 6 percent on rising hopes that top producers would agree to freeze output and positive economic indicators in the United States and Europe hinted at an increase in demand.
Yellen said on Thursday the U.S. economy was on a solid course with some hints of inflation, putting the central bank on track for a gradual increase in interest rates this year.
New York Fed President William Dudley said a cautious and gradual approach to raising rates was appropriate, given lingering external risks to the U.S. economy.
U.S. stocks have been volatile through the week, with the S&P 500 down 1.5 percent, as investors fretted over a cloudy outlook on rates and signs of weakness in the global economy. Continuación...