During a statistics class at Howard University yesterday, students and instructor alike pushed aside probability theory and talked about a more concrete issue: why Nelson Mandela would not visit their school.

In the alumni office, when the telephones rang this week, half the callers were as likely to ask whether Mandela would visit their alma mater as about financial contributions to the university.

And wherever Palesa Makhale went on campus this week, the South African-born woman who leads the Howard Foreign Students Association was asked by faculty, staff members and students why Howard was not on Mandela's itinerary.

"There is a real sense of disappointment, of being left out," said Makhale, 28, a graduate student in psychology. "Everyone wants to know why Howard, one of the most prominent black universities in this country, was not included in the historic visit."

It was not for a lack of trying.

Howard University President Franklyn Jenifer "promised" in an interview with The Washington Post two months ago that the freed deputy president of the African National Congress would spend "twice as much time at Howard University" as he would at the White House.

But when the first tentative schedule was released in early June, Howard was not on it. Howard officials said Jenifer lobbied hard to get organizers to fit Howard into Mandela's crowded schedule. He called TransAfrica. He called the ANC. He called Roger Wilkins, the national coordinator for the trip. He called labor leaders.

When the first and second round of calls did not work, Jenifer called again. Administrators who were close to top people on the organizing committee called too.

A visit from Mandela would have fit perfectly with Jenifer's plan to bolster Howard's national image by marketing the university's ties with Africa and the Caribbean.

"His visit is something we would have cherished for a long time," Jenifer said in an interview this week. "We certainly would have been honored for him to have visited us."

Christine Dolan, spokeswoman for the national organizing committee, said that Howard was not included because Mandela's schedule is filled with "serious work," such as meetings with President Bush and congressional and labor leaders.

Mandela will visit a prominent predominantly black institution. He is expected to attend a one-hour ceremony Wednesday in the Martin Luther King Jr. Memorial Chapel at Morehouse College in Atlanta.

All 115 historically black or mostly black colleges were invited to participate in the ceremony, during which each could give Mandela an honorary degree. As of yesterday, 30 institutions had confirmed their participation. Howard University is not among them.

Jenifer said he does not think Howard was slighted by the schedulers. "I am sure that Mr. Mandela is aware of Howard's role in educating many people from Africa," he said.

For a while, Winnie Mandela had been scheduled to speak at Howard. But that event also was canceled.

Makhale was understanding about the matter.

"At this point in time, he can only do so much," said Makhale, who will sing Tuesday with other members of the local South African community before Mandela's speech at the Washington Convention Center. "I think this is not his last trip to the United States. And maybe he will come to Howard the next time."