The saying, "One robin does not mean spring," means most nearly: (a) Do not be convinced by a single sign; (b) Events may have many interpretations; (c) A single stroke fells not the tree; (d) Experience teaches us to judge closely; (e) All signs fail in dry weather.

The above question is designed to test reasoning, and it is a sample from the examination given to prospective District of Columbia police officers -- an exam that, when given last March 28, produced results that Mayor Marion Barry and city officials said discriminated against blacks and women.

Barry announced earlier this week that the city will lower the passing score on the examination, known as Test 21, from 40 to 35 correct answers out of a possible 80 in order to include more blacks and women in a pool of 635 applicants. Then the 635 names will be drawn at random so that the top finishers, most of them white males, will have no more chance than anyone else of being chosen first to join the D.C. police force.

Although the lottery system has been used in other cities, Barry's decision drew some criticism from police union officials who said the city was unfairly changing the rules for those who scored well on the test.

Union officials, such as International Brotherhood of Police Officers President Larry Simons, said they thought there would be little effect from the lowering of the passing score from 40 to 35, noting that standards at the city's police training academy will not be lowered and that marginal police candidates could still be weeded out there.

But some police officers disagreed, including Det. George Steel, an eight-year veteran.

"What we could end up doing is hiring a bunch of incompetents," Steel said. "It's embarrassing...and it's dangerous. If a man can't articulate, he's going to have to resort to violence more often."

Steel added that the issue of lowering the passing test score has brought added racial tension to the department, with some whites resenting what they see as an attempt to add more blacks to the force at the expense of minimum standards.

The test that has created the controversy was first developed in 1946 by what was then the federal Civil Service Commission, now called the Office of Personnel Management, according to Helen Christrup, director of personnel research and development for OPM.

"It's a test of verbal ability, and it's one of our standard tests," Christrup said. "We find that verbal ability is very basic to the ability to learn. The test is a high predictor of the ability to learn in police academies. As a rule of thumb, this test is about at the high school graduation level."

The test has been used for D.C. police officers since 1948 and in the past has been given to D.C. firefighter applicants and such federal police officers as the U.S. Park Police. But now no other law enforcement agency uses Test 21.

Parts of the test are still used in exams given to a wide range of federal job applicants, Christrup said, but the only groups that take the test in its entirety are prospective government travel clerks, mapmaking aides and D.C. police officers.

The test was upheld for use in the D.C. police department in 1976 by the Supreme Court in a case originally brought by blacks who contended that the test discriminated against them.

"Test 21...seeks to ascertain whether those who take it have attained a particular level of verbal skill; and it is untenable that the Constitution prevents the Government from seeking modestly to improve the communicative abilities of its employees rather than to be satisfied with some lower level of competence," wrote Justice Byron White in a 7-to-2 majority opinion.

But the court's decision was based on the Constitution, rather than the stricter requirements for racial balance found in Title VII of the Civil Rights Act, which did not then apply to the federal or D.C. government. In an executive order mandating the use of the lottery system and the lowering of the test scores, the mayor indicated the city feared a discrimination challenge under Title VII.

Although 75 percent of those who took the test on March 28 were black, Barry reported that 62 of the top 100 scores were made by whites. Women were also underrepresented among the top scorers.

The March testing was the first for which the city had sole responsibility; previously, the federal government administered the test. The city could have used another test or developed its own, but decided that there was not enough time to do so. In a letter to the chairman of the House subcommittee on D.C. appropriations, which has been pressuring the city to hire 200 additional police officers, Barry wrote that last winter he was not even aware that the responsibility for giving the test had passed to the local government.

Not all jurisdictions follow the District's approach of giving a verbal ability exam to police candidates. Some, including Montgomery and Prince George's counties, use a test prepared by the Educational Testing Service, which also prepares such exams as the Scholastic Aptitute Test for college entrance.

The county test includes questions to test vocabulary, but primarily consists of questions related to police work, like the ability to fill out police forms and to notice details at a crime scene. It has survived court tests on discrimination, according to a spokeswoman for the International Personnel Management Association, and is made available to police departments for about $5 a copy.

Oh, yes. The answer to the question at the top of the story is (a).