The Education Department is investigating whether Seattle’s public school district discriminates against black students by subjecting them to tougher and more frequent discipline than white students, agency and district officials said, Reuters reports. The inquiry, launched in May 2012, is focusing in part on the district’s own statistics showing that African-American high school students are suspended or expelled more than three times as often as other students, school officials said on Wednesday. In middle school, the racial disparity is greater, with blacks 3 1/2 times more likely to be disciplined than other students, according to district data shared with Reuters. More than a quarter of all black middle school pupils have received short-term suspensions in any given year since at least the 2006-07 academic year, compared with 7.4 percent or less annually for white students, the data shows…