For every two shares falling, nearly three gained on the New York Stock Exchange, where 2 billion shares traded. Composite volume cleared 5.2 billion.
The dollar fell against major U.S. trading partners, and the 10-year Treasury yield used in determining mortgage rates and other consumer loans dropped 3 basis points to 2.744 percent.
Crude-oil futures for May delivery rose 56 cents to $99.46 a barrel; gold futures for April delivery added $5.50, or 0.4 percent, to $1,336.00 an ounce, down 3.4 percent for the week.
On Thursday, stocks advanced to recoup most of the prior day's losses, after upbeat economic reports and as investors reconsidered Yellen's remarks on Wednesday, which sparked concern about the timing of when the central bank hikes short-term interest rates, currently at record lows.
"What we've seen this week is every piece of economic data has been incrementally better than expected. We've had a major concern there was a soft patch in the economy and all the weather-related things represent pent-up demand, so we could have a better spring than expected," said Hogan.
"Broadly speaking, the market is digesting the Fed's decisions, in terms of (Fed Chair Janet) Yellen and her preference for guidance," said James Liu, global market strategist at J.P. Morgan Funds.
Investors who had priced in the Fed funds rate being about 25 basis points higher at the end of 2015 are now looking "at mid-2015, so June probably," said Liu, who added: "with the economy improving, this will be easily digested."
In remarks released Friday, Minneapolis Fed Bank President Narayana Kocherlakota said the central bank should have vowed to keep rates near zero until unemployment falls below 5.5 percent, so long as inflation and financial stability risks are contained. Kocherlakota was the lone dissenter to the Fed's policy decision on Wednesday.
Late Thursday, the Federal Reserve said big U.S. banks have sufficient capital to weather a dramatic economic downturn, with 29 of 30 major banks meeting the minimum bar in the central bank's yearly check. The sole bank to fail the test, Zion Bancorp said it would resubmit a capital plan to the Fed.