Two social scientists who conducted an opinion survey in Prince George's County at the request of defense lawyers for Terrence Johnson concluded that 25 percent of the blacks in the county believe that when "the Prince George's police arrest someone, that person's life is in danger," according to a summary of the study released yesterday.

Johnson is a 16-year-old black youth accused of murdering two white Prince George's County police officers last June 26. His lawyers asked the National Jury Foundation, a non-profit organization of lawyers, legal workers, and social scientists, to conduct the study, and hoped to use it to support the defense argument that Johnson acted in self-defense when he shot one of the police officers.

The survey conclusions were drawn from 329 telephone interviews by about 50 volunteers under the supervision of Richard Seltzer, a political science professor at Howard University. Some of the volunteers, Seltzer said yesterday, where active supporters of Johnson's defense.

The study showed that 85 percent of the black community and over 40 percent of the white population "believed police brutality to be a serious problem in the county," according to Seltzer and Robert Turner of the National Jury Project.

A summary of the survey showed that 30 percent of blacks and 7 percent of whites interviewed strongly agreed with the statement "black youth have good reason to fear the Prince George's County police," Fifty-two percent of blacks and 18 percent of whites strongly disagreed with the statement "the Prince George's County police never hit people without good reason," the summary said.

According to the study summary, 51.3 percent of those interviewed believed that Johnson was either "definitely guilty" or "probably guilty" of the murders of officers James Brian Swart and Albert M. Claggett.

Almost 17 percent of those questioned said they believed Johnson was definitely or probably innocent, while 31.9 percent had no opinion.

The study findings were released at a press conference yesterday organized by Johnson's defense lawyers and a group supporting him, the Coalition to Free Terrence Johnson. Circuit Court Judge Jacob S. Levin, who is hearing the case, refused to admit the study into evidence last week.

Prince George's Police Chief John W. Rhoads was unavialable for comment yesterday. Police spokesman John Hoxie said, however, that there had been "a dramatic decrease" in brutality complaints in the county over the past three years.

Hoxie noted that several cases of alleged police brutality had received wide publicity both in 1976 and more recently, but said that police administrative rules were changed several years ago to ensure accurate reporting of such cases, and that "the word is out that we won't stand for [brutality by police]."

Hoxie said: "What we're seeing is a lingering image that comes from several years ago and earlier. But we just don't have the problem we did. It's to the point where we feel we've put that problem behind us."