What was going on when I was born?

An article on Monday about American companies that are weeding out operations misstated General Electric's involvement in the production of its CAT scanners. The company's Japanese joint venture makes 25 percent of them; G.E. manufactures the rest itself in the United States.

International Israeli planes bombed the P.L.O. headquarters near Tunis in what Israel said was retaliation for the slaying of three Israelis in Cyprus last week. Yasir Arafat, the Palestine Liberation Organization chairman, was visiting a P.L.O. installation in northern Tunis when the Israeli jets struck his offices south of the capital. He was not among the wounded. [Page A1, Columns 4-6.] The White House said that Israel's attack on the P.L.O. headquarters in Tunisia appeared to be ''a legitimate response'' against ''terrorist attacks.'' [A1:4-5.]

SOME years ago a woman I worked with married for the third time. The single state made her jumpy - she called it ''being at loose ends'' -so for her, marriage was not only a commitment to someone else but a concession to a rotten nervous system. Then she started making lists. They were shopping lists. ''Brie,'' she would say in the middle of office meetings. ''I think Brie with pears, don't you? And maybe veal scalloppine first, with rice and a salad.'' Her cronies, myself among them, were stunned. We knew this woman for a noncook and a noneater, and here she was, carrying on like Betty Crocker. What we didn't realize, of course, was that never before had we seen her at the beginning of a marriage. Had we been witnesses to the weeks following her previous weddings we might have heard the same musings. ''Brie, I think Brie with pears . . .''

Major international banks agreed yesterday to postpone nearly $1 billion in loan repayments from Mexico, averting what could have been one of the largest defaults since the debt crisis began in August 1982. By itself, the loan rescheduling is one of many that banks have been forced into with third world borrowers. But, coming as it does when the United States is attempting to encourage increased lending to the third world - by commercial banks, the World Bank and the International Monetary Fund - the rescheduling could provide fresh momentum to efforts to resolve the debt crisis. At a Washington meeting yesterday, Treasury Secretary James A. Baker 3d and Paul A. Volcker, the chairman of the Federal Reserve Board, appealed to bankers to aid in solving the problems. [Page D12.] Six-Month Postponement In the Mexican situation, after a number of all-day meetings in New York with Mexican officials, 13 lenders headed by Citibank said they had agreed to put off for six months $950 million in payments. Some of them were due yesterday and the rest were due Nov. 4. The lenders, which call themselves Mexico's ''bank advisory committee,'' and which represent roughly 600 lenders worldwide, said in a statement that they would use the six months to study financing requirements of Mexico and the resources available to it ''from international financial institutions, bilateral sources, and the private sector.''

With increasing urgency, the industrial nations and the third world have been sparring recently over whether to remove barriers to the free trade of services. The developed countries, paring down their traditional manufacturing industries and relocating plants overseas, have been eager to enter new markets with such services as banking, insurance, communications and data processing. The third world nations have strenuously resisted, fearing that free trade in this area would threaten their own struggling efforts in the sophisticated services sector and restrict their economies to an agrarian and manufacturing role. The smoldering dispute broke out into the open here today, when the United States-led campaign to include services in any new global trade talks ran into fierce third world opposition at a meeting of the General Agreement on Tariffs and Trade.

THE value of teaching parents how to rear their babies - what to say to them even before they know how to speak, what toys to choose - has been demonstrated in four Missouri school districts. The toddlers, by age 3, showed mental and linguistic growth far exceeding that of other children. In one of the first experiments of its kind to be rigorously evaluated, trainers regularly visited homes, starting during the pregnancies of mothers-to-be and continuing for three years. They provided information on subjects as varied as how to detect symptoms of fluid and congestion in the middle ear, which could diminish hearing ability and impede language development, to how to discipline infants without punishing them. The results, based on an outside evaluation, are to be announced today in St. Louis by Arthur L. Mallory, Commissioner of the Missouri Department of Elementary and Secondary Education, which sponsored the project.

Twenty-five years ago the Oba, or tribal chief, of Lagos paid $2,800 to rainmakers to insure that a sudden downpour would not spoil the ceremony in which the British flag would be lowered for the last time and the green-and-white banner of the new country raised in independence. Today, as the country's latest military ruler stood at attention watching precision marching by army and navy units, smartly turned out in new dress uniforms in Tafawa Balewa Stadium downtown, it poured. The ceremony was to observe the 25th anniversary of independence. ''In these economic hard times, we can't afford such things,'' said a newly appointed Government official squeezed under a canopy, a frail refuge from the sheets of warm rain that lashed the heavy concrete stadium.

Richardson-Vicks Inc., makers of Vicks cold remedies, has agreed to sell the company to Procter & Gamble, the consumer products giant, for $69 a share, or about $1.55 billion in cash, the two companies announced yesterday. The decision, following secret round-the-clock negotiations with three suitors for the last three days, appeared to bring to an end an attempt by Unilever N.V., the Dutch-British concern, to buy Vicks against its will. Humphrey Sullivan, a spokesman for Unilever, said the company might have a comment today about its next move, but a series of precautionary measures taken by P.&G. and Vicks seemed tailored to discourage Unilever from further efforts to take over the company. Stock Rises On the New York Stock Exchange, where Vicks's stock stood at only $40 when Unilever first showed interest early last month, Vicks ended the day at $68, up $4.50, on a volume of 1.4 million shares.

A solid majority of the members of the House Ways and Means Committee expressed support today for legislation that would place a 40 percent top tax rate on individuals, according to people who were present at the debate. President Reagan supports a maximum rate of 35 percent, and Administration officials have said he is adamant against raising it. The highest rate now is 50 percent. The committee, in its second day-long closed session to draft a tax-revision bill, did not take any votes today. But committee members said afterward that the sentiment for a higher top rate than the President had proposed became apparent after a long discussion of the issue.

A report on Monday in the Southwest Journal column misidentified a Phoenix lawyer who is considered a possible Democratic candidate for Governor of Arizona. He is Tony Mason.

Stocks of companies involved in takeovers dominated the list of the percentage gainers on the nation's major stock markets for the quarter ended Monday. Other companies made it to the top because of strong earnings or such diverse reasons as heavy demand for military boots and the popularity of Dr. Ruth Westheimer, the sex therapist. Meanwhile, companies beset by a variety of troubles, ranging from bankruptcy to import competition, topped the list of the biggest losers. The third quarter was not a good one for most stocks, following widespread gains in the first and second quarters. According to a compilation of 4,307 stocks by Media General Financial Services of Richmond, 2,738 lost ground on the New York and American stock exchanges and in the over-the-counter market in the summer quarter, with 1,366 up and 203 unchanged. During the second quarter, of the 4,332 stocks tracked, 2,278 were higher, 1,841 were lower and 213 were unchanged.

Israeli planes flew 1,500 miles to Tunisia today and bombed the headquarters of the Palestine Liberation Organization south of Tunis, the capital. Israeli officials said the attack was in retaliation for the slaying of three Israelis in Larnaca, Cyprus, six days ago. P.L.O. officials in Cyprus denied at the time that they or any group affiliated with the P.L.O. was responsible. A P.L.O. spokesman said 60 people were killed in the attack today, ''including women and children, many of them Tunisians.'' The Tunisian authorities said 60 people were wounded, 25 severely.