NEW YORK (TheStreet) -- Stocks moved higher on Friday after Federal Reserve Chair Janet Yellen removed some of the doubt over the central bank's plans for an interest rate hike.

The S&P 500 was up 0.7%, the Dow Jones Industrial Average added 1.1%, and the Nasdaq gained 0.39%.

In a speech at the University of Massachusetts on Thursday, Yellen made the case for a rate hike this year, though argued that the decision would continue to rely on economic data. Yellen said that inflation would build gradually over the next few years.

"Most FOMC participants, including myself, currently anticipate that achieving these conditions will likely entail an initial increase in the federal funds rate later this year, followed by a gradual pace of tightening thereafter," Yellen said.

Markets have been erratic since the Fed decided to leave rates unchanged at their meeting last week with investors interpreting that as another sign of uncertainty.

"The reason why the stock market traded off after [the Fed's decision to hold rates] was it created a lot of doubt in the minds of investors about the health of the U.S. economy," Don Ellenberger, senior vice president at Federated Investors, told TheStreet. Yellen "created a lot of uncertainty about what the Fed's strategy was for when they would begin raising rates."

The final read on consumer sentiment in September moved higher to 87.2 from an initial reading of 85.7, according to the University of Michigan. The measure was above economists' estimates, though well below a reading of 91.9 in August. 

The U.S. economy grew at a 3.9% annual pace in the second quarter, the Commerce Department said Friday. The GDP estimate was the second revision, up from a prior estimate of 3.7%. Consumer spending rose 3.6% from an initial estimate of 3.1%.

Volkswagen (VLKAY) is expected to announce its new CEO on Friday. CEO Martin Winterkorn, who resigned on Wednesday, will reportedly be replaced by Porsche's CEO Matthias Muller in the wake of a massive emissions scandal, according to The Wall Street Journal. Earlier this week, the German automaker admitted that more than 11 million diesel vehicles had software that gamed emissions tests.

Marvell Technology(MRVL) - Get Report added 3.6% after announcing plans to cut around 17% of its work force. The layoffs are expected to save between $170 million and $200 million annually. 

In earnings news, BlackBerry (BBRY) fell more than 2% after another weak quarter. The company reported a net loss of 13 cents a share, 4 cents wider than expected, while revenue tumbled 47% to $490 million.

Pier 1 Imports(PIR) - Get Report fell nearly 20% after quarterly profit missed estimates and full-year guidance was slashed. The retailer expects full-year profit as high as 64 cents a share, below previous guidance of 83 cents to 87 cents a share.

Bed, Bath & Beyond(BBBY) - Get Report shares were on watch after a weak quarter. Same-store sales rose 0.7%, or 1.1% on a constant-currency basis, well below estimates for 2% to 3% growth. The retailer also announced a $2.5 billion share buyback program.

Nike(NKE) - Get Report added 9.3% after reported net income of $1.34 a share, 15 cents above estimates, in its first quarter. Sales rose 14% on a constant-currency basis, while future orders jumped 9%. By brand, Nike sales gained 15% and Converse revenue climbed 3%.