BROOKLYN - Education officials have confirmed that an investigation is under way at two Williamsburg schools to determine if teachers improperly coached students during exams. Officials say the investigation involves P.S. 31 and P.S. 257. They say children from those schools typically move on to I.S. 318, and teachers there raised concerns. The teachers found that several students' work was far worse than their scores from the previous year would have suggested.The Department of Education says a jump in test scores isn't necessarily evidence of cheating, but says that any such allegation warrants an investigation.