What was going on when I was born?

President Reagan's search for remedies for the nation's economic problems continued to dominate his working schedule today as he met with Republican Congressional leaders and announced his intention to appoint Murray L. Weidenbaum to be chairman of the Council of Economic Advisers. At midday, Mr. Reagan left the White House for a ''get-acquainted'' luncheon in the Treasury building with Paul A. Volcker, the Federal Reserve chairman, whose monetary policies he has often criticized. The message emerging from Mr. Reagan's breakfast meeting with the Congressional leaders was that his package of economic proposals would not be sent to Congress until mid-February, well behind the original schedule set by the Reagan transition team. Decisions on Former Hostages While concentrating on the economy, Mr. Reagan was also making the broad policy decisions about the homecoming of the Americans formerly held hostage in Iran, according to James S. Brady, the White House press secretary. He said it was Mr. Reagan's decision that the former captives should meet privately with their families on Sunday, their first day back in the United States, before coming to the White House on Tuesday to be welcomed by Mr. Reagan.

Samuel Barber, the American composer who twice won the Pulitzer Prize and whose Adagio for Strings became one of the most popular works in the orchestral repertoire, died yesterday in his Fifth Avenue apartment after a long illness. He was 70 years old. Throughout his career, Samuel Barber was hounded by success. Probably no other American composer has ever enjoyed such early, such persistent and such long-lasting acclaim. His first piece for orchestra, Overture to ''The School for Scandal,'' which he composed at the age of 21, was given its world premiere by the Philadelphia Orchestra under Alexander Smallens. Arturo Toscanini, who in his later years wanted little to do with new music, chose to give the world premieres of two Barber works in one year, the ''First Essay for Orchestra'' and the orchestral version of the Adagio for Strings.

The freed American hostages will be flown home Sunday to be reunited with their families at the United States Military Academy at West Point. Some, according to the State Department's chief medical officer, will bring with them serious psychiatric problems growing out of their 444 days of captivity. After four days of tests and rest, the State Department said, the former hostages are scheduled to make the last leg of the long journey home from Teheran when they board an Air Force jet at Frankfurt, 20 miles from here, for a flight to Stewart Airport at Newburgh, N.Y. From there, the freed hostages and their relatives will be transferred to the United States Military Academy for several days of privacy. One Will Stay in Germany Only 51 of the 52 who had been held in Teheran will will be making the trip. Donald R. Hohman, an Army medic, has already been reunited with his German-born wife, Anna, and has chosen to remain in Frankfurt with her and their two children.

As the Soviet Union stepped up pressure against Poland today and Warsaw was crippled by a four-hour strike, Lech Walesa issued an appeal for members of Solidarity, the independent trade union organization, not to work tomorrow. ''There must be an effective work boycott tomorrow to preserve the unity of the movement,'' Mr. Walesa said in a statement that was telexed and telephoned to Solidarity offices throughout the country. ''We know that there are 10 million of us,'' he said. ''Ten million members that should be talked to, dealt with and not split. Everything is directed at splitting us. If we are divided here, we will be divided on other matters.

The Consumer Price Index, continuing to climb sharply, rose by 1.1 percent in December, the Bureau of Labor Statistics reported today. For all of 1980, the bureau reported, the rise was 12.4 percent, the second consecutive year of double-digit inflation as measured by this index. The 1979 rise was 13.3 percent. Not since World War I have there been two such consecutive years.

With almost uncontainable joy, the families of the freed Americans prepared yesterday to go to West Point for the reunion tomorrow that has been more than 14 months in coming. ''We're in a euphoria,'' said Dorothea Morefield, the wife of Richard H. Morefield, the former Consul General at the United States Embassy in Teheran. ''Right now,'' she said at her home in San Diego, ''everything's on clouds. Everything's beautiful. Everything's gorgeous. He's fine, we're fine. Next week I may feel differently. But I can't think about that today. Right now, I'm on my way to see my husband.''

The Times of London explained today that Rupert Murdoch, the publisher of The New York Post, had been chosen to be its new owner because he offered the paper the best chance of becoming financially successful while preserving its editorial independence and journalistic excellence. In a long editorial entitled ''The Future of The Times,'' the paper said that of the prospective purchasers only Mr. Murdoch met all the criteria that had been set, including ''financial competence, management capacity, the willingness to make a resonable commercial offer, and finally and crucially, the willingness to guarantee future editorial independence.'' The editorial was an attempt to counter the shock and dismay that has spread through parts of the British Establishment since the announcement yesterday that Mr. Murdoch, who is widely regarded as a publisher of lowbrow sensationalism, was planning to add The Times and its affiliated publications to his press empire. As Mr. Murdoch began the trade union negotiations upon which his offer to buy the papers is conditional, there were demands in the House of Commons that the Government act to halt it.

Ecuador has protested to Peru over an incident in which it says a Peruvian helicopter fired on an Ecuadorean border post, seriously injuring a soldier, the Foreign Ministry said.

Talking Businesswith William R. Dill of N.Y.U. U.S. Course For Chinese Last spring, China invited a team of professors at American business schools, sponsored by the United States Department of Commerce, to inaugurate its new National Center for Industrial Science and Technology Management at Dalien, a northeastern industrial port. The result was an 18-week course, which ended Dec. 20, for Chinese managers, Government officials and professors who will be teaching business management at Chinese universities. Designed to introduce the Chinese to American business practices and business school teaching techniques, the course used a mixture of American and Chinese case studies and included a computer-based management game. William R. Dill, a 50-year-old New York University professor of management and organizational behavior who last summer completed a 10-year stint as dean of N.Y.U.'s School of Business Administration, served as dean of the visiting faculty. In a recent interview, he discussed the program.

The national police said today that the Jan. 12 shooting of a Bedouin Member of Parliament was carried out by three sons of the Druse sheik who inherited the dead man's legislative seat. Comdr. Yehezkel Carthy, head of criminal investigations, said at a news conference that the three - identified as Daish, Seif and Hail Muadi, sons of Sheik Jaber Muadi - were arrested soon after the Bedouin, Sheik Hammad Abu Rabia, chief of one of the largest tribes in the Negev, was shot in his car outside Jerusalem's Holy Land Hotel.

The West German Justice Minister was elected Mayor of West Berlin today. The choice of Hans-Jochen Vogel was seen here as proof of the seriousness with which the Bonn Government viewed the political situation in West Berlin after the surprise resignation last week of Mayor Dietrich Stobbe and his entire Social @Democratic-Free Democratic cabinet. The vote for Mr. Vogel in the city parliament was 73 to 60, with 2 abstentions. The Christian Democrats, the largest single parliamentary group, have 63 members, while the coalition partners, the Socialists and the small Free Democrats, together command 72 votes, which meant that at least one of the opposition members had voted for Mr. Vogel.

The United States welcomed today the decision by President Chun Doo Hwan of South Korea to commute to life imprisonment the death sentence imposed last fall on Kim Dae Jung, the opposition political leader. ''We believe this action will contribute positively to the strengthening of relations between the United States and South Korea,'' William J. Dyess, the acting State Department spokesman, said. President Chun's commutation took place early today shortly after the South Korean Supreme Court had affirmed the death penalty for sedition against Mr. Kim, who was convicted last September. The fate of the 56-year old political figure became a major issue between the Carter Administration and President Chun.