Answer by taking a quote from the following article:

Howard Brush Dean III (born November 17, 1948) is an American physician, author and retired politician who served as the 79th Governor of Vermont from 1991 to 2003 and Chair of the Democratic National Committee (DNC) from 2005 to 2009. Dean was a candidate for the Democratic nomination in the 2004 presidential election. His implementation of the fifty-state strategy as head of the DNC is credited with the Democratic victories in the 2006 and 2008 elections. Afterward, he became a political commentator and consultant to McKenna Long & Aldridge, a law and lobbying firm.

Dean graduated from Yale University with a Bachelor of Arts in political science in 1971. As a freshman, he requested specifically to room with an African-American. The university housing office complied and Dean roomed with two Southern black students and one white student from Pennsylvania. One of Dean's roommates was Ralph Dawson, the son of a sheet metal worker in Charleston, South Carolina and today a New York City labor lawyer. Dawson said of Dean:  Unless you operated from a stereotypic understanding of the Yale white boy as rich, you wouldn't know that about Howard.... When it came to race- and I don't know whether this was a function of intent or just came naturally- Howard was not patronizing in any way. He was willing to confront in discussion what a lot of white students weren't. He would hold his ground. He would respect that I knew forty-two million times more about being black than he did. But that didn't mean he couldn't hold a view on something relating to civil rights that would be as valid as mine. There were lots of well-meaning people at Yale who wanted you to understand that they understood your plight; you'd get into a conversation and they would yield too soon, so we didn't get the full benefit of the exchange. Howard very much thought he was capable of working an issue through. He was inquisitive. And when he came to a conclusion he would be as strong as anybody else. I don't think he's stubborn. He's a guy who's always been comfortable in his own skin. That's something you still see in him today, and it gets him into some degree of controversy.  Though eventually eligible to be drafted into the military, he received a deferment for an unfused vertebra. He explained to Tim Russert on Meet the Press, "I was really in no hurry to join the military." He briefly tried a career as a stockbroker before deciding on a career in medicine, completing pre-medicine classes at Columbia University. In 1974, Dean's younger brother Charlie, who had been traveling through southeast Asia at the time, was captured and killed by Laotian guerrillas, a tragedy widely reported to have an enormous influence in Dean's life; he wore his brother's belt every day of his presidential campaign.

What did Dean do at Yale?
As a freshman, he requested specifically to room with an African-American.