NEW YORK — Wall Street plunged yesterday after the Federal Reserve lowered interest rates by a quarter point, disappointing investors who hoped the central bank would move more aggressively to help the economy overcome the credit and mortgage crisis. The Dow Jones industrial average skidded more than 290 points.

Investors had been expecting policymakers would lower rates for a third straight time, though there was debate over the size of the cut. Most economists anticipated a quarter-point reduction in the benchmark federal funds rate to 4.25 percent, but some investors were hoping for a half-point cut from the Fed's final meeting this year, and their disappointment took the market sharply lower.