The Obama administration set new terms for private Medicare plans that are aimed at protecting sick patients from paying high charges and giving consumers a clearer idea of what the plans cover. The changes, announced by the Centers for Medicare and Medicaid Services, are part of conditions that insurance companies must meet if they want to bid on Medicare insurance business this year. Administration officials said the changes are intended to weed out certain out-of-pocket costs charged by Medicare Advantage, the private version of the federal health-insurance program for the elderly.