U.S. inflation in the first half of the year was probably “markedly lower” than reported, but policymakers are unlikely to set interest rates incorrectly as a result, according to an analysis published Monday by the San Francisco Federal Reserve Bank. Researchers at the regional Fed bank had earlier found that the very weak readings for economic growth in the early part of the year were likely due to inadequate adjustments for seasonal fluctuations, and that true economic growth was probably much faster than reported.