What was going on when I was born?

Because of an error by the Associated Press, a picture caption in some copies of Sports Pages yesterday incorrectly identified a Yankee infielder taking a throw at second base at a game in Chicago Tuesday night. He is Willie Randolph.

For the more than 70 percent of American workers who are not covered by a collective bargaining agreement or an individual employment contract, dismissal is an ever-present possibility. The nation's courts have traditionally ruled that such employees can be dismissed at any time - for any reason or for no reason - a status known as ''employment at will.'' That status is becoming a thing of the past, though, as more and more courts around the country are taking steps to help protect workers, either by finding in the working arrangement an implied contract or implied guarantee of fair dealing, or by going even further and finding that unjust dismissal was a civil offense for which the employer should pay punitive damages. In New York and several other states, courts have found implied contracts, and therefore legal protection against dismissal, in the statements of company policy found in employee handbooks.

As many as 17,000 families are illegally doubling up in apartments in New York City's public projects because of the economy and the shortage of housing for the poor, according to estimates by city officials. The City Housing Authority says the number, which represents about 10 percent of all families in public projects, is the largest since immediately after World War II, when returning veterans married and moved in with tenants in the projects. ''The problem is growing geometrically,'' said Joseph J. Christian, chairman of the Housing Authority. ''It's a human tragedy and an administrative nightmare.''

To many New Yorkers, the changes taking place at Citibank branches around the city are jarring, if not infuriating. Some of the changes seem downright discriminatory against people with little money, such as a policy being introduced that forces Citibank's low-balance customers to use machines rather than human tellers. And the changes are coming so quickly and in so many areas that many people - customers and employees alike - are having a hard time understanding them. Although it seems at times that Citibank goes out of its way to antagonize customers, William J. Heron Jr., the Bronx-bred, 41-yearold senior vice president in charge of metropolitan-area branches, said that the bank's sole objective is to give the public what it wants. That, he continued, is the only way the bank will be able to serve all consumers, rich and poor, and still make money.

A pink diamond valued at $500,000 to $600,000 was reported stolen from Sotheby Parke Bernet galleries the afternoon before it was to be auctioned, the police said yesterday. Appraisers at the Manhattan auction house discovered the theft when they found that the 9.58-carat diamond had been replaced by an inferior diamond colored with pink nail polish. While bidders filled the gallery at York Avenue and 72d Street yesterday, spending $6.6 million on jewelry, police officers and the Federal Bureau of Investigation worked to solve what a police spokesman called ''the mystery of the big switch.'' The mystery: How was the emerald-cut diamond removed from its locked glass display case and switched with the nail-polished gem during the presale exhibition in a room filled with Sotheby's workers and armed guards and monitored by videotape cameras?

A committee of Reagan Administration officials has proposed a law under which any Government employee who improperly discloses classified information would be subject to a criminal penalty of three years in prison and a fine of up to $10,000. The committee, in an internal report, said, ''Unauthorized disclosure of classified information has become an increasingly common occurrence.'' However, it added, ''There is no single statute that makes it a crime as such for a Government employee to disclose classified information without authorization.'' Support From Administration Thus, the panel said, ''to close the gaps in the present law, we recommend the introduction of legislation imposing a criminal penalty for all unauthorized disclosures of classified information by Government employees'' and former employees.

Under this heading, the Times amplifies articles or rectifies what the editors consider significant lapses of fairness, balance or perspective. Corrections, also on this page, continue to deal with factual errors.

Brazil announced today that it had decided not to permit four Libyan planes, detained since Saturday, to proceed to Nicaragua with tons of arms and explosives. The Reagan Administration said the munitions might have been destined for insurgents in El Salvador. The White House, seeking support for the Salvadoran Government and striving to draw attention to accusations of Nicaraguan subversive activity in El Salvador, also said that President Reagan would defend his Central American policy before a joint session of Congress next Wednesday night. This is to be Mr. Reagan's most comprehensive address on Central America. The Administration is trying to counter the lack of Congressional support for its Salvadoran aid program and the seeming parallel lack of concern about the activities of the Cuban- and Soviet-backed Nicaraguan Government.

Spurred in part by a sharp jump in housing construction, the nation's economy grew at an annual rate of 3.1 percent in the first quarter, the largest quarterly rise in two years, the Commerce Department reported today. Economists said the rise in the gross national product, the broadest measure of the nation's economic activity, was the surest sign to date that recovery from recession was moving ahead. The economy declined 1.1 percent in the fourth quarter of 1982 and fell nine-tenths of 1 percent for all of 1982. Nevertheless, the 3.1 percent rise in the first quarter, after adjustment for inflation, was smaller than some economists had predicted and also less than the 4 percent rise estimated by the Commerce Department last month, before the quarter ended.

An interagency committee has reported to President Reagan that it believes the Soviet Union has violated terms of the 1979 strategic arms accord, and the Administration is under pressure from conservative senators to make that finding public, officials disclosed today. The officials said the President, prompted by the report, had appointed a new panel headed by William P. Clark, the national security adviser. The panel will begin meeting this week to check ''all aspects of compliance'' with nuclear arms treaties to see whether there has been a pattern of Soviet violations and to consider what action Washington should take. 'A Fairly Long List' Officials said the new panel would examine ''a fairly long list'' of potential violations under the 1979 strategic arms agreement, the 1972 Antiballistic Missile Treaty, the 1974 Threshhold Test Ban Treaty and the 1976 Treaty on Peaceful Nuclear Exchange.

DESIGN trends at the Southern Furniture Market this month came wrapped in traditional packages. Rather than emphasize innovative styles, many of the 1,300 manufacturers simply used new fabrics and finishes to dress up furnishings from previous markets. In contemporary upholstered pieces, the rainbow of pastel shades evident during the past two years was replaced by primary colors; black, lipstick red and navy blue were dominant. Case goods - dining and bedroom sets - wore sophisticated lacquer finishes.

International Four Libyan planes bound for Nicaragua with tons of weapons and explosives will not be allowed to proceed, Brazil announced. The Reagan Administration said the arms might have been destined for insurgents in El Salvador. (Page A1, Column 2.) Apparent Soviet arms violations have been reported to President Reagan by an interagency committee, according to officials. They said the White House was under pressure from conservative senators to make public evidence that reportedly shows that Moscow has violated terms of the 1979 strategic arms control treaty. (A1:3-4.)