What was going on when I was born?

The House Ways and Means Committee today voted against requiring corporations and banks to withhold 10 percent from dividend and interest payments for taxes. The action came on a voice vote on a measure to repeal the withholding, which is scheduled to go into effect on July 1, The vote cleared the way for a floor debate on the issue next week. The House is all but certain to vote to repeal withholding from interest and dividend payments and the Senate is on record favoring a plan to postpone the effective date of the provision until 1987. But President Reagan is a strenuous advocate of withholding and is likely to veto a measure that eliminates or postpones it.

Commuters on the Long Island Rail Road - long accustomed to wondering whether the 7:25 A.M. will arrive before the 7:12 - have recently been playing a different kind of guessing game. Some riders refer to it as railroad roulette, and the object is to guess which four stations the L.I.R.R. will eliminate as part of a $146.5 million modernization program. The guessing began when the railroad announced two months ago that it planned to electrify the 25 miles of track between Hicksville and Ronkonkoma now served by diesels. Electrification would mean a faster commute, shaving an estimated 20 minutes off the current 72-minute trip to Pennsylvania Station from here, the railroad says.

A bill that would allow a judge to lengthen the prison term of anyone wearing bulletproof clothing while committing a violent crime received final approval yesterday in the New York State Legislature. Under the measure, wearing the clothing during such a crime would itself be a felony, and one to four years could be added to the defendant's sentence. The bill passed the Assembly yesterday by a vote of 135 to 1. It was approved by the Senate on Monday. The measure's chief sponsor in the Assembly, John C. Dearie, Democrat of the Bronx, said he expected Governor Cuomo to sign the bill.

Braniff International's board of directors agreed in principle last night to a proposal by the Hyatt Corporation that would allow the grounded airline to resume some flight operations. The plan calls for Hyatt to raise $70 million in return for 80 percent of the new airline's stock. However, Howard D. Putnam, Braniff's chairman, said that the plan still needed the approval of the bankruptcy court as well as Braniff's secured creditors. They have rejected earlier Hyatt proposals and have generally maintained that they would receive more through liquidation than might be earned by reviving some of Braniff's routes.

Henry Ford developed the moving assembly line into one of the most bountiful production systems ever known. Here, at the Ford Motor Company's light truck assembly plant, they think they have improved on the founder. They stop the line. It only stops for about 30 seconds in one location, just long enough for a pair of workers to lower the cab of a Ranger pickup truck or the body of a Bronco 2 utility vehicle onto the chassis. That brief pause, however, makes it a lot easier for the two workers to position the body and place it on the chassis without damage. ''There's no jogging, no guessing: You just line up two pins and drop it,'' said Nicholas Hertelendy, manager of manufacturing engineering at the plant. ''Can you imagine how hard you would have to work to do that on a line moving at rate of 75 an hour?''

Every year for almost a century before World War II, Rockland County held a country fair and exposition. Now, for the first time in 43 years, that practice is resuming. Today through Sunday at Rockland Community College in Suffern, N.Y., there will be events including a 1940's dance contest tonight at 7; a 4-H fair and horse show and an antique-car display, both tomorrow, from 10 A.M. to 5 P.M.; a dog show, same hours Sunday, and a rodeo Sunday at 2. Exhibits on commerce and industry, health, culture and other subjects can be seen and ethnic foods consumed in the Field House. Crafts will be sold, and a farmers market and entertainment are also planned. Directions: (914) 786-3131. Admisision: $2.50 ($2 for over-65's, $1.25 for under-16's). TAP DANCING TO BACH Tapping to everything from ''You're a Lucky Girl'' to a Bach prelude and fugue, Jane Goldberg's Changing Times Tap Dancing Company and a guest, Leon Collins, will appear in the Riverside Dance Festival, Riverside Drive and 120th Street, tonight at 8 and tomorrow and Sunday at 2 P.M. The show, called ''The Depression's Back (& So Is Tap),'' will include traditional jazz tap as well as ''rappingtapping dialogues,'' which include talking, and tap done to reggae and Carribean rhythms, to new music and to such older works as ''The Flight of the Bumblebee.'' Tickets: $6 ($4 for students and over-65's). Reservations: 864-2929.

IF springtime is a time for singing, New York is living up to its responsibilities this weekend. Singers of blues and ragtime, singers who use their voices as jazz instruments, singers of Kurt Weill, of Latin American art songs, of the repertories of Bessie Smith and Edith Piaf can all be heard over the next few days and nights in supper clubs, cabarets, college auditoriums and Central Park. In every case these singers are women, a coterie that includes Linda Hopkins, Martha Schlamme, Nancy Wilson, Sheila Jordan, Odetta, Carrie Smith, Janet Lawson and Nacha Guevara. Two of these larks of May, Sheila Jordan and Janet Lawson, are in the forefront of jazz singers today whose voices are part of an instrumental ensemble. Miss Jordan, who began singing in the 1940's under the musical influence of the saxophone playing of Charlie Parker, has been working for the last four years with the Steve Kuhn Quartet, in which she is a fourth voice, along with Mr. Kuhn's piano, Harvie Swartz's bass and Bob Moses' drums. She vocalises some passages as part of the ensemble; at other times, she uses lyrics in a way that has the improvisatory nature of her vocalising, colored by earthy growls and high, glistening shimmers of sound.

The Chrysler Corporation, responding to an outburst of criticism, said today that it was giving up its efforts to keep the Government from profiting on Chrysler stock that it has the right to purchase. The auto maker said that it no longer was seeking to cancel warrants that give the Government the right to buy 9 percent, or 14.4 million shares, of Chrysler at $13 a share. The stock closed today on the New York Stock Exchange at 25 1/2, down 5/8.

An article May 5 on the mayoral pri mary in Gary, Ind., incompletely re called previous elections of black mayors. On Nov. 7, 1967 - the same day that Richard Hatcher was elected in Gary - Carl Stokes was elected the first black mayor of Cleveland, a much larger city.

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.

Foreign Minister Elie Salem of Lebanon arrived here tonight in an effort to persuade Syria to drop its objections to the agreement on the withdrawal of Israeli troops from Lebanon. Mr. Salem met with President Hafez al-Assad of Syria and other officials and was expected to hold more meetings Friday. There was no early sign that Mr. Salem had made any headway, and the statecontrolled radio continued to denounce the Israeli-Lebanese accord worked out last week by Secretary of State George P. Shultz. (In Beirut, the Cabinet held a three-hour meeting without giving its formal endorsement to the Israeli-Lebanese agreement, but the approval is expected later. In Washington, the State Department said the Reagan Administration was contemplating direct talks with Syria on the issue of troop withdrawals. Page A7 and A8.)

The Manville Corporation yesterday made public a plan of reorganization that it wants to propose to its creditors - including thousands of claimants with asbestos-related diseases - if the parties involved in the company's bankruptcy negotiations do not reach agreement soon. The plan calls for Manville, which filed for protection from its creditors under Chapter 11 of the Federal bankruptcy laws last August, to spin off its non-asbestos operations into a new company that would be immune from the asbestos claims. Although Manville is the world's largest asbestos producer, asbestos products account for only 5 percent of its revenues; the rest comes chiefly from glass fiber, forest products and roofing. A portion of the new company's earnings would go to pay the 16,500 asbestos-related personal injury claims that led Manville to seek court protection, as well as claims by banks, suppliers and insurance companies. All claims against the company were frozen by the bankruptcy filing.