US STOCKS-Wall St to dip at open after two-day rally
* Yelp climbs on deal with Yahoo
* Hasbro falls after earnings
* McDonald's posts January sales
* Futures off: Dow 21 pts, S&P 3.75 pts, Nasdaq 1.75 pts
By Chuck Mikolajczak
NEW YORK, Feb 10 (Reuters) - U.S. stocks were set for a slight decline at the open on Monday, indicating the S&P 500 would retreat after its best two-day performance in four months, ahead of new Federal Reserve Chair Janet Yellen's first testimony before lawmakers on Tuesday.
* The benchmark S&P 500 rallied Friday for the index's first weekly gain in the past four, as investors looked past a disappointing payrolls report.
* Despite the soft payrolls data, affected partly by frigid weather, the Federal Reserve is largely expected to continue its efforts to scale back its stimulus.
* Yellen's first test as chair of the Federal Reserve comes Tuesday when she faces U.S. lawmakers, some hostile to the central bank, who will want to know how committed she is to winding down the Fed's support for the economy. Continuación...