Dow Jones industrial average plummeted 67.63 points, closing at 3869.09 . . . N.Y.S.E.'s composite index dropped 3.72, to 255.91 . . . NASDAQ stock lost 7.76, to 768.96 . . . American Stock Exchange fell 2.98, to 458.15 . . . Gold up $3.60, to $393.60 on the Commodity Exchange in New York . . . The 30-year Treasury bond closed with a yield of 7.77 percent, up from 7.75 late Monday.