WASHINGTON (AP) _ A son of NAACP president Kweisi Mfume has been sentenced to four years and nine months in prison for federal drug and weapons convictions.

Ronald T. Gray, 29, pleaded guilty last October, admitting he sold cocaine in Washington for more than two years. At his arrest last May, federal Drug Enforcement Administration officers found cocaine, a scale, packaging materials and $8,500 cash at his District of Columbia home.

``Mr. Gray was a calculated drug dealer,'' U.S. District Judge Henry H. Kennedy said Friday, before giving him time less than minimum recommended under federal sentencing guidelines. A drug conviction for amounts of cocaine between 3.5 and 5 kilograms carries penalties of 70 to 87 months in federal prison.

Kennedy said the guidelines were too severe because of Gray's efforts toward rehabilitation since his arrest. Gray has regularly attended Alcoholics Anonymous meetings to hasten his rehabilitation and has lived in a halfway house while working as a restaurant busboy.

Mfume, who once used the name Frizzell Gray, was in the courtroom with other family members. The NAACP president was among several family members who pleaded for leniency.

``It is very humbling to have to acknowledge that it is your own child'' who has problems, said the former four-term Maryland congressman.