Gains by blacks and other minority students on this year's college entrance exams were largely responsible for the first increase in average scores in 19 years, the College Board announced yesterday.

Black scores rose by an average of 9 points on the verbal part of the 1982 Scholastic Aptitude Test (SAT) and by 4 points on the math section, compared with results in 1981. Whites gained 2 points on the verbal test and nothing in math.

Therefore, the College Board said, this year's overall 3-point rise in SAT scores, which had been dropping steadily since 1963, "was due significantly to improvements in minority group scores."

As a group, black students still trailed their white classmates in 1982 by an average of 103 points on the verbal test and 117 on the math, on a scale ranging from 200 to 800. But the latest figures released by the New York-based group show that this gap, made public for the first time last week, has been narrowing over the last six years.

Combined scores on the two-part test have increased an average of 21 points for blacks since 1976. Average white scores have dropped 17.

"As a whole, minorities are making progress in closing the gap that exists between their scores and that of the white majority," said George H. Hanford, president of the College Board. One official said the board has tried to remove questions that might be culturally biased against minority students, but that this effort began in the 1960s and shouldn't have affected the more recent scores.

From 1976 to 1982, the data show, SAT scores for white students declined from 451 to 444 on the verbal section and from 493 to 483 on the math test.

But during the same period black scores on the verbal test rose from 332 to 341, while Mexican-American scores increased from 371 to 377. For Asian-Americans, verbal scores dropped from 414 to 398. Puerto Rican scores dipped from 364 to 360. On the math test, blacks have raised their scores from 354 to 366 over the six-year span. Math scores increased by 3 to 6 points for Mexican-Americans, Puerto Ricans and American Indians.

Hanford said these scores have increased since 1976 even though more minority students have been taking the test, which tends to cause average scores to decline. The percentage increase in students taking the test ranged from 24 percent among blacks to 97 percent among Asian-Americans.

Hanford cautioned that the disparity between white and black scores among the nearly 1 million students taking the SAT is still significant and "reflects an educational deficit that must be overcome."

Last week's announcement, which showed black high school students trailing whites by 110 points on the verbal portion and 121 points on the math, was based on an analysis of the 1981 test. Those figures showed that among both races students from families with the least income and education had the lowest scores.

Ann Cleary, director of evaluation services at the University of Iowa, said the new figures may reflect the impact of financial aid programs that over the last 15 years have enabled more low-income blacks to set their sights on a college education.

"That's a strikingly large gain for such a big sample," she said. "The trend is clearly upward for the black youngsters. We may finally be getting the message down to black youngsters that going to college is a viable option. We may have changed their aspirations. If these young people at 13, 14 and 15 are attending more to their schoolwork and taking college preparatory courses it's the most wonderful news I've heard in a long time."

As for why whites' scores continued to decline during this period, Cleary said it remains a puzzle.

"Experts will give you 200 reasons why test scores have gone down, including everything from television to sunspots," she said.