The economy last month shook off most of the sluggishness caused by the winter freeze and natural gas shortages as the number of persons with jobs grew by more than 500,000 and the unemployment rate fell from 7.5 per cent to 7.3 per cent, according to the Department of Labor.

The department said that all the reduction in unemployment occurred among adult men.

Still, the number of persons out of work and looking for jobs stood at 7.1 million in March, about the same level of unemployment as in March, 1976. Over the year, though, the number of people with jobs climbed from 86.8 million to 89.5 million.

The March jobs figures confirm what the administration has been saying since January: that the winter freeze would have a severe, but temporary impact on the economy.

Despite the rebound from the cold weather and two years of recovery from the worst recession in the post-war era, the unemployment rates for nearly all groups -- the general labor force, married men, adult men and full-time workers -- remain "at unprecedented high levels by historical standards," according to Commissioner or Labor Statistics Julius Shiskin.

Testifying before the congressional Joint Economic Committee, Shiskin noted that unemployment among teenagers has not abated and said that "their unemployment rate remained close to the high levels reached in early 1975 at the peak of the recession."

Shiskin said the nation has a two-tier unemployment problem, with teenagers, especially black teenagers, on one tier and most other workers on another.

Shiskin noted that since the eight-month slowdown in the economy recovery ended last October, employment has risen "vigorously" at about 350,000 jobs a month.

Bert Lance, director of the Office of Management and Budget, told reporters yesterday that the administration is pleased with the continuing improvement in the economy.

But he said the economy still needs the boost that the President's proposed $50-a-person rebate would give. People expect the checks, Lance said, and have adjusted their spending with them in mind.

That rebate has run into strong opposition in the Senate, and Lance said that if a vote were held in the Senate today, passage would be "iffy."

Lance also said that the administration has not yet decided whether to ask business to give advance notice of price increases in the anti-inflation program the President plans to announce next week.

Business will be asked to impose price restraints and to resist anticipatory price increases, but whether it will be asked to tell the administration before it changes prices is up in the air.

"Personally, I think you need an element" of pre-notification so officials can keep informed of what is happening in the private economy, Lance said.

The Labor Department's Shiskin said yesterday there has been "an acceleration in the rate of increase in consumer prices in the first two months of the year." But he said it is not yet clear whether the price increases mean the 5 to 6 per cent inflation track most economists think the economy has been on will increase.

Much of the two-month acceleration was due to food and fuel price rises, which rose sharply in the winter freeze. Shiskin noted that the rate of inflation has accelerated in most other industrial countries in recent months.

The 7.3 per cent unemployment rate matches the January rate, which was the lowest rate since the end of the recession in 1975. The jobless rate, which is seasonally adjusted, is the percentage of the labor force that is unemployed but actively seeking work. The labor force is made up of those with jobs and those looking for them. The rate is based on a monthly survey of 47,000 households.

A survey of payrolls, which economists say is more accurate but less comprehensive than the household survey, also showed an increase of 500,000 jobs.