April 13, 1982

''I enjoy proving the experts wrong.'' - Nicholas F. Brady, named to be United States Senator from New Jersey. (B5:4.)

An unexpected shortage of substitute teachers is troubling schools in New York City and other urban centers around the United States. It is forcing principals to search desperately each day for replacements for absent teachers and it often disrupts the normal education of students. Sometimes principals themselves take over classes because no substitutes are available. At other times, youngsters whose teachers are absent are required to spend the day sitting in the school auditorium because there is nobody to teach them.

The small symbol of the Republic is safe now, nestled to the body of its nursemaid 80 feet off the ground in the tower of a pine at the edge of Bear Swamp. Earlier today there was some doubt about their meeting, some fear the one might reject the other. Perhaps even kill it. Still, all went well, and now New Jersey's only pair of nesting bald eagles, which for six years have been unable to produce a viable egg, have a chick. The state wildlife officials who introduced the laboratory-born eaglet into the nest of its wild surrogate parents this morning hope that the chick will signal a resurgence of the species here.

Retail sales fell 0.5 percent last month, the Commerce Department said, and they are likely to stay sluggish in the second quarter, Commerce Secretary Malcolm Baldrige predicted. The results contrasted with a 2.6 percent rise in February that apparently only temporarily stemmed two previous declines. (Page D1.) February installment debt grew by only $75 million in February as consumers reduced credit purchases because of the recession. The rise, at an annual rate of gain of less than 0.5 percent, compared with an annual growth rate of 6.8 percent a year earlier. (D8.) The Fed tentatively decided to change the way it reports weekly money supply figures, shifting to a four-week moving average. The change is an effort to lessen the numbers' impact on financial markets. (D1.)

The Federal Reserve Board tentatively decided today to change the way it reports weekly money supply numbers, in an effort to lessen their impact on the nation's financial markets. The board, at an open meeting, reached a consensus to report each Friday afternoon the average of the most recent four weeks of money supply growth or decline, instead of changes in the money supply for the previous week only. The board said that it was also considering delaying the release time of money supply figures from the current 4:10 P.M. on Friday to 5 P.M. or later to be sure that most markets, including those on the West Coast, were closed before the figures were released. But there was no tentative decision on this issue. Under the current system, the Fed's money supply announcement sometimes affects late-afternoon trading in fixed-income securities, causing yields to rise or fall.