By John S. McClenahen Just how good was the first calendar quarter of 2002 for the U.S. economy? The U.S. Commerce Department gives its preliminary answer Friday, April 26, when it releases GDP figures at 8:30 a.m. EDT. Merrill Lynch & Co., true to its corporate symbol, is bullish. The New York-based securities firm is estimating January through March growth at an inflation-adjusted annual rate of 6%, a full percentage point higher than the consensus number of 5%. Merrill Lynch believes inflation, using GDP calculations, should be just 0.9%. Meanwhile, Maury Harris, chief U.S. economist at UBS Warburg, New York, has more modest expectations. He anticipates a 4% rise in real GDP during the first three months of 2002, with inflation at 1%. As for the current quarter, Merrill Lynch says the economy is advancing at a 4% annual rate; Harris puts GDP growth at 3%.