Internal Revenue Service agents gave incorrect information one out of four times last year when helping people prepare their tax returns, but the IRS has vowed to do better this year.

"We were not satisfied with the results of last year . . . (only) three out of four questions were answered properly," said IRS Commissioner Lawrence Gibbs at a news conference kicking off the 3 1/2-month tax-filing season ending April 15.Gibbs said the IRS would use more experienced people in 1989 than in 1988, when the agency hired about 1,000 agents to help handle the inquiries.

"More experienced people can do a better job in answering the questions more accurately," Gibbs said. "We are looking to improve . . . substantially over last year. We are cautiously optimistic," Gibbs said.

He urged taxpayers to file early to assure accuracy. "There really is a direct correlation between the accuracy of the returns that are filed and the time in which they are filed."

Gibbs said about 20 percent of taxpayers wind up paying the wrong tax. "Our error rate, the taxpayer's error rate and the preparer's error rate is about 20 percent," he said.

The error rate for those filing electronically through computer is only 3 percent, Gibbs said, and the IRS is expanding the number of districts capable of handling electronic returns from 16 to 48.

The agency expects as many as 2 million electronic returns compared to the 583,000 filed in 1988, Gibbs said. Over 109 million returns are anticipated overall compared to 107 million in 1988, he said.

Of these, 75.2 percent received refunds averaging $905, Gibbs said. They are expected to average about the same amount this year, he said.

Gibbs said the most common error was the taxpayer's failure to claim the standard deduction and to check the box if claimed as a deduction by someone else.