What was going on when I was born?

After a period of reassessment, China has unveiled an economic blueprint for the next five years that sticks firmly to the ''open door'' policies charted at the beginning of the decade by the country's pragmatic leader, Deng Xiaoping. Despite the troubles that have beset the Deng program in the last year, the new economic plan for 1986 to 1990 underlines the commitment to expanded foreign investment and trade. It also cautiously renews the effort to spur production by loosening central economic controls. The decision to grant wider autonomy to some 400,000 state and collective enterprises, announced last October, led to a free-for-all that caused a major crisis by the early months of this year. A huge borrowing spree, compounded by widespread corruption, led to a precipitate fall in the foreign exchange reserves to $11 billion in March from more than $16 billion.

A dispatch from Phoenix yesterday on Senator Barry Goldwater incorrectly described former Senator Hugh Scott of Pennsylvania. He is alive.

The Defense Department, in an effort to cut its long-range spending plan without reducing its nuclear weapons program, has approved sweeping cutbacks in projected spending on conventional military forces, according to Reagan Administration officials. In a process described as painful and divisive, senior Pentagon officials have been rewriting their five-year plan for weapons, personnel and operations in light of Congress' success in ending the Reagan Administration's military buildup. Delays in Purchases The cuts will mean long delays in the scheduled replacements of older tanks, aircraft, ships and missiles, the officials said in interviews over the last week. They will also sharply curtail efforts in the next five years to replenish stockpiles of ammunition and spare parts, key indicators of the ability to outlast an enemy in a conventional war, the Pentagon officials added.

In a move with broad implications for American eating habits and food assistance programs, a committee of the National Academy of Sciences has drafted a report calling for lower recommended levels of some vitamins and minerals needed to maintain health. The authors of the report said that it was based on the best available scientific data. But some nutrition experts, including people asked by the academy to read the report as part of its internal review process, expressed concern. They said the report on the Government's recommended dietary allowances could be used by officials to justify further cuts in food stamps, school lunch subsidies and other feeding programs. If, for example, the recommended allowances for vitamins A and C were reduced, school lunch menus might not need as much fruit and vegetables.

Joking that ''I hurt my arm bowling,'' Billy Martin, the embattled manager of the Yankees, showed up at Memorial Stadium today with a broken arm following an early-morning punching, kicking, grappling brawl with Ed Whitson, one of his pitchers. The fight, which began in a hotel bar but extended to the lobby and then outside before ending verbally on the third floor, was the second incident in 24 hours in which Martin was involved in the bar of the Cross Keys Inn, where the Yankees stay here. The incident early Saturday morning, involving a man Martin had been drinking with, was generally verbal, although Martin later acknowledged, ''I didn't get to him, but I wanted to.'' After Martin and Whitson returned to their rooms following their fight, a Yankee source said, Martin telephoned Whitson in his room and challenged him to go out to the parking lot and continue the fight, but the 30-year-old pitcher declined. George Steinbrenner, the Yankees' principal owner, hadn't been able to receive reports on the first incident when the second occurred.

The Economy The United States and four other major countries said they were prepared to work together to drive down the value of the dollar. The countries - Britain, West Germany, France, Japan and the U.S. - stopped short of saying they would intervene in currency markets. But the threat to do so was clear if the marketplace does not restrain the dollar's rise. [Page A1.] Congressional Democrats termed the action an important philosophical shift for a President who has seadfastly proclaimed the benefits of a strong dollar. [D12.] Participants in foreign-exchange markets differed in their assessments of the impact that the group's stand would have. [D12.]

To the relief of many leaders of the savings and loan industry, the Federal Home Loan Bank Board is expected to decide within the next 10 days to form a new institution that would relieve its beleaguered deposit insurance unit of some $3 billion in troubled assets. Not only would this new unit free the cash-strapped Federal Savings and Loan Insurance Corporation from the burden of selling illiquid properties, such as half-finished office buildings and undeveloped land, but it also would give the F.S.L.I.C. more than $2 billion in highly liquid securities that it can cash in whenever it needs fresh infusions to prop up or take over tottering thrift institutions. ''We are taking this recommendation under serious advisement,'' said Donald I. Hovde, a board member. He added that the board is meeting this week with the 12 regional Home Loan Bank presidents to discuss the issue and that he hopes the bank board's staff will give the three-member board a detailed recommendation to vote on by its next meeting on Oct. 2.

Finding the high value of the dollar unwarranted, the top economic officials of the United States and four other major industrial countries said yesterday that they were prepared to work in concert to drive the dollar down. The countries - Britain, West Germany, France and Japan, along with the United States - did not say specifically that they would sell their treasuries' vast holdings of dollars to try to force the decline and thus make other currencies rise. But the threat to do so was clear if the marketplace does not. The commitments the countries made yesterday could be of some economic and political significance. Not once since 1973, when the world's currencies were left to ''float'' in the foreign-exchange markets to seek their own value, have countries contracted to try to alter their currencies' values.

FACING reality could have been as numbing as the sting of a crisp left jab, the kind Larry Holmes boasted would land like a hammer on Michael Spinks's jaw. Instead, Spinks awoke on the first day of his reign as the International Boxing Federation heavyweight champion in a more euphoric daze, still unable to appreciate the impact of what he had accomplished. He sat lazily on a sofa in a Riviera Hotel meeting room where he was interviewed by CBS, dressed casually in a red warmup suit, but not wearing shoes or socks. He twitched and turned uncomfortably, much the way he had slept, Spinks said. In an era of showmanship and false bravado, Spinks came across as refreshingly unaffected and a bit giddy with success. He looked at a front-page newspaper photograph showing him and Holmes exchanging punches and said jokingly, ''Look at him. He's scared to death.''

With great pomp and ceremony, an international airport opened 16 years ago in this tiny rural community in the Catskills 100 miles north of New York City. The Sullivan County International Airport was paid for with $4 million from the Federal Government and $2 million from the county. Local officials anticipated cavalcades of jets unloading swarms of tourists ready to play the casinos that long have been discussed as a way of rejuvenating the area's depressed economy. But the slot machines never came and the jets never arrived.

Despite the fact that inventories of heating oil are currently at their lowest level in years, most oil experts expect supplies to be more than adequate during the winter season. This means, they said, that consumers should face at most only slight increases in retail prices from last winter's moderate levels. The analysts said that the continued moderation in heating oil prices, a byproduct of the decline in crude oil prices, foretells a furthering narrowing of the gap between the cost of heating a home with fuel oil and the traditionally lower cost of heating residences with natural gas. ''If the U.S. has a normal winter, I don't see any problems whatsoever,'' said John H. Lichtblau, president of the Petroleum Industry Research Foundation.

The 40th meeting of the United Nations General Assembly will require more than half the Secret Service agents in the nation, about 10 percent of New York City's police force, Coast Guard patrols on the East River and a new computer system to coordinate an unparalleled mobilization of city, Federal and international security agencies. After months of planning, the combined security operation will encounter its first major test today when American and foreign leaders begin arriving in New York. Among those scheduled to address the Assembly today are Secretary of State George P. Shultz and President Jose Sarney of Brazil. In the next five weeks, as many as 59 heads of government, including President Reagan, and 159 foreign ministers are to be in New York to mark the 40th anniversary, speak before the Assembly and attend diplomatic meetings and receptions. The session will provide the backdrop for the largest international gathering of leaders at United Nations headquarters.