The typical Miami rioter is 27.8 years old, an unmarried male who quit high school before the end of his senior year and believes America is not worth fighting for.

He's a blue-collar worker who earns less than $10,000 a year. The rioter is dissatisfied with his neighborhood and his home. He says blacks elsewhere earn more money than he does. He's never been arrested.

The Miami rioter is a registered voter who has cast a ballot in at least one election during the past two years.

He believes the criminal justice system discriminates against blacks.

He's angry, bitter -- and much like the nonrioter.

This profile emerges from a survey of 444 blacks in five riot-torn areas of Miami and surrounding Dade County conducted by The Miami Herald and the Behavioral Science Research Institute of Coral Gables. The Washington Post helped support the poll.

The poll showed some differences between Miami riot participants and nonrioters. It also disclosed ominous similarities that indicate the problems and frustrations of the riot participants are widely felt in Dade County's troubled black neighborhoods.

For the purposes of the study, a riot participant was identified as anyone who said he or she was slightly, somewhat, or actively involved in the May 17-19 disturbance. Surveys of black attitudes in Watts, Detroit and Newark -- including the Kerner Commission report in 1968 -- used the same method to define riot participants.

The Herald poll included the opinions of 112 persons who said they participated in the rioting.

Blacks who joined in the rioting were generally decidedly younger than nonrioters. Age emerged as the single controlling factor in determining riot participation, a finding consistent with earlier riot participation studies.

While the average age of the rioter was 27.8 years, the mean age of the nonrioter was 38.1. The true average age of the riot participant likely is slightly lower. To help avoid misleading results, only persons 15 years old or older were interviewed.

When questioned about the extent of 23 problems in the black community -- ranging from unemployment and poverty to poor schools and dirty neighborhoods -- the perceptions of riot participants varied dramatically from those of nonrioters in only three areas.

Significantly fewer riot participants identified "parents unable to control their children," "too much drinking" and "too much drug use" as major problems -- differences that perhaps could best be explained by the relative youthfulness of the riot participants.

Other differences emerged, though all were characteristic of the relative youthfulness of the riot participants, analysis of the riot and nonriot populations disclosed.

Rioters were more likely to say that blacks in other cities had better jobs, higher incomes and better educations.

And they were far less likely to agree that voting is the only way that blacks are "able to have a say." Four out of every five nonrioters agreed with that statement. Fewer than three out of five rioters agreed.

Slightly more than half of the rioters -- 51 percent -- said that blacks would gain more by the riot than if the disturbance had not occurred. Fewer than 45 percent of the nonrioters agreed, though 30 percent of that group said they weren't sure, while only 19 percent of the rioters were undecided.

Rioters paid a price for that expected progress. Slightly more than 18 percent of the rioters said they or a family member lost a job because of the disturbance. Seven percent of the nonrioters said they or their relatives lost a job.