What was going on when I was born?

The plans for Bryant Park change it markedly while preserving its best features. An appraisal, page B2. An unusual public-private partnership is planning an $18 million redevelopment of Bryant Park that will include a huge glass restaurant, a cascading fountain with reflecting pools, four food kiosks and a permanent security force. The design would fill the nine-acre greensward behind the New York Public Library at Fifth Avenue and 42d Street with tables and chairs for 4,000 people. It was prepared by the nonprofit Bryant Park Restoration Corporation, the New York Public Library and the Department of Parks and Recreation.

Large pension funds and other institutions may have fueled the bull market over the past year, but so too did married, working, college-educated women in their 30's, who were living in large metropolitan areas and were members of households with incomes of just over $30,000. That is the profile of the typical new stock market investor, according to a New York Stock Exchange survey made public today. The exchange found that 42.4 million Americans, or a record 18.1 percent of the population, owned shares either directly or through mutual funds. The figure was up from 14.4 percent in 1981, when the last survey was conducted, and 11.9 percent in 1975, and does not include stocks that individuals own indirectly through pension funds.

The Westinghouse Electric Corporation, the big industrial conglomerate, has a microwave radio system that permits telephoning among its 22 buildings in or around Pittsburgh without using the local phone company's lines. The arrangement deprives Bell of Pennysylvania of $500,000 to $1 million a year in transmission revenues and even more in equipment rentals. Westinghouse is only one of many big companies finding more and more ways to get along without the telephone company. Increasingly, businesses are exploiting new technology to make their calls or transmit data, both locally and over long distance, without using local phone lines. And as businesses reduce their reliance on the telephone network, rates for other telephone users may have to go up, to make up for the lost revenues. Exactly how fast or furiously this phenomenon - which is known as bypass - will unfold is hotly debated. Some say the trend is greatly overblown. Still others say, however, that with the breaking up of the Bell System Jan. 1, bypass will accelerate. In any case, the phone companies have apparently concluded that bypass cannot be halted: Rather than fighting the trend, many are gearing up to compete with other companies in offering bypass services.

Ten policemen raided an unguarded warehouse here today and freed the kidnapped brewery chairman, Alfred H. Heineken, and his chauffeur from unheated concrete cells in which they had been chained for 21 days. The police later arrested 24 suspects, all Dutch citizens related to each other by blood or marriage, and said they were hunting for four others. The rescue of the two men, who were said to be cold but in good health, came two days after a ransom payment rumored to exceed $10 million was made on a road outside the central Dutch city of Utrecht. At least part of the ransom was reportedly recovered in the homes of the suspects in Amsterdam, in suburban Zwanenburg and in Helder, a port 50 miles to the north.

BILLY BALDWIN always insisted that he never originated anything in decorating. Yet, the Baltimore-born decorator, who died at the age of 80 last Friday on Nantucket, left an indelible stamp on American interiors. His rooms sparkled with freshness and a sense of ease, qualities rooted in his love of Matisse, his Southern past and his talent for eliminating whatever he deemed superfluous. The decorating prescriptions devised by Mr. Baldwin, a small, impeccably dressed man known for his sharp eye and sharper tongue, were executed for wealthy, socially secure clients. In diluted form they swept through post-World War II America: colorful rooms, generously patterned and furnished with plump upholstered seating.

-story office building called Cityplace will open in Hartford. With 1.3 million square feet of floor space, it will be the largest commercial structure in Connecticut. It will also be ''the world's first intelligent building,'' according to one company involved, the Building Systems Company. Later next year, Building Systems, a subsidiary of the United Technologies Corporation, says, it will complete work on the first ''intelligent'' buildings in New York City - Tower 49 - and in the Southwest - LTV Center in Dallas. And it is also installing sophisticated office complexes outside Washington, D.C., at Crystal City in Arlington, Va., and Skyline City in Alexandria, Va.

President Reagan and his senior national security advisers agreed in principle today to proceed with the development of weapons capable of repelling nuclear attacks by destroying incoming missiles, according to an Administration official. The official said, however, that Mr. Reagan had not yet made key decisions on the kind of technology, the level of financing for next year and other aspects of the proposal. He first advanced it last March, creating an immediate furor. Mr. Reagan was said to be leaning against the recommendation of some members of Congress that the United States should embark on a program to deploy defensive weapons quickly.

New York City's plan to invest $20 billion in public works will produce ''demonstrable improvements'' in bridges, hospitals, water supply, pollution control and waste disposal by 1992, according to a new study. But streets and public school buildings, it concluded, ''are likely to deteriorate further.'' The condition of police and fire installations as well as vehicles for all the uniformed services will remain about the same, according to the study by the Citizens Budget Commission. The outlook for the city's water mains, sewers, parks and jails is uncertain, at best, the report said. The commission made its predictions in a 102-page review of the 10-year plan for capital development unveiled last year by Mayor Koch. The panel, made up mostly of bankers and businessmen, has monitored city finances for more than 50 years.

When Rose Brush owned her house, the walls were falling apart, the front steps and interior stairs were crumbling with age, the water heater was worn out, the windows were drafty and the gas company was threatening to shut off service for nonpayment. Although there were was no mortgage, Mrs. Brush found that with income of $900 a month, medical bills of her own and two disabled children to care for, she could not afford repairs and taxes. So, 20 years after moving in, she lost the place, and signed a lease with the new owner, who rebuilt the front steps and replaced the water heater, windows, doors and bathroom fixtures. The new owner also put a new sink and reconditioned stove into the kitchen, started work on the uneven floors and walls all over the house, took over the gas payments, put in a $1,000 replacement water main and promised to paint the interior and exterior. All this for $100 a month in rent, an amount that probably will not cover even the gas bill. Her new landlord is the City of New York, which gained title to the 100-year-old house in September 1982. Mrs. Brush - who has been hospitalized frequently in recent years with phlebitis and a weak heart and whose husband has been institutionalized since 1974 - could not pay the $2,000 in property taxes due on the house.

Prices farmers get for raw products rose seven-tenths of 1 percent in November after declining two months in a row, the Agriculture Department said today. The increase was indicated by preliminary figures that showed higher prices for corn, oranges, eggs, broilers and cotton during the month.

Robert Austin Sullivan, a convicted murderer whose fight to avoid execution was embraced by Pope John Paul II and deplored by the Chief Justice of the United States, died today in the electric chair. As supporters and opponents of the death penalty staged orderly vigils outside the state prison here, a hooded state executioner sent a two-minute, 2,000-volt charge of electricity through Mr. Sullivan's body at 10:11 A.M. The jolts were activated with the shift of a lever controlling electrodes attached to Mr. Sullivan's head and lower right leg. Both had been shaved earlier in the morning to insure contact with the electric charges. Mr. Sullivan, 36 years old, was pronounced dead at 10:16 A.M. The execution was carried out ''very smoothly,'' said Vernon Bradford, state corrections spokesman.

A question and answer in some copies of the News Quiz last Saturday incorrectly described a name change in Westchester County. The prison at Ossining is once again called Sing Sing; the surrounding village retains the name Ossining.