The Washington Post incorrectly reported Thursday that Barbara Lett Simmons (At Large) was among four D.C. school board members who had opposed the appointment of Floretta D. McKenzie in a preliminary vote during a closed board meeting Wednesday night. Only three members -- R. Calvin Lockridge (Ward 8) John E. Warren (Ward 6) and Frank Shaffer -- Corona (At Large) -- opposed the McKenzie appointment in that vote.

A bitterly divided D.C. School Board last night chose Floretta Dukes McKenzie, a former acting head of District public schools, as the new superintendent of the city's troubled 99,000-student school system.

However, in an unpreacedented agreetment worked out between McKenzie and the 11-member board, her tenure in the $55,400-a-year post will be tied directly to the terms of a "letter of understanding." Under the agreement, details of which had not been worked out last night, McKenzie's performance is to be evaluated by the board every six months and judge primarily on improvement in student achievement.

McKenzie, 45, was chosen on a 7-to-4 vote over Acting Superintendent James T. Guines, the after leading contender, on the first and only vote in a closed three-hour board session that sources described as rancorous and divisive.

The choice of McKenzie was later formally approved at a public board session, during which members who had supported Guines complained bitterly that there had been no opportunity for discussion of candidates in the private session before the vote on McKenzie was called.

"Why the hell did you hail me down here if you ween't going to ask me who was my first choice, said R. Calvin Lockridge (Ward 8) during the public session.

Glaring sternly at the audience of mostly school system employes and reporters, John E. Warren (Ward 6) complained angrily that McKenzie "was not my choice and not the choice of the majority of the people I have heard from."

Barbara Lett Simmons (At large) accused her fellow board members of engaging in an "unhealthy, unwholesome" action during the closed session and proposed during the open session that Guines' term be extended until March of 1982, when the term of former Superintendent Vincent E. Reed was to have expired.

The proposal was defeated by a vote of 7 to 4, with Lockridge, Simmons, Warren and Frank Shaffer-Corona (At large) -- the same members who voted against McKenzie in closed session -- voting in favor.

The formal vote to appoint McKenzie was then taken, with eight members, including Simmons who switched her vote, in favor. Lockridge and Warren abstained, and Shaffer-Corona voted present.

Member Linda Cropp (Ward 4), who had been McKenzie's chief supporter on the board, said McKenzie was chosen over Guines because, although Guines has the instructional and curriculum skills, "Mrs. McKenzie has . . . managerial skills" as well. "Guines was a little weak on the managerial skills," she said.

Referring to the board's desire to appoint someone already familiar with the D.C. school system, member Carol Schwartz (Ward 3) pointed to McKenzie's "invaluable experience both within this school system and on the federal level. She should offer stability to the system."

Schwartz said she believed McKenzie would face rough times before the board since she was not its unanimous choice.

"This board certainly has individuals on it who are not going to make life easy for any superintendent. I think the vote tonight paints a realistic picture of what Mrs. McKenzie is going to have to face. I admire her courage for accepting the superintendency in spite of the knowledge that she was not the number one choice for certain board members," Schwartz said.

McKenzie headed the D.C. schools as acting superintendent from July 1, 1973, to Sept. 30 of that year before Barbara Sizemore was selected superintendent.

Described by those who know her as strong-willed, aggressive and gregarious, McKenzie was the deputy superintendent of schools in Montgomery County until 1978 when she went to the U.S. Department of Education as a deputy assistant secretary in change of innovative programs.

In narrowing the number of finalists for the District superintendency, several board members said they had been impressed with McKenzie's wide range of administrative experience, and the range of her contacts in education, both on the national and local level. She received a letter of recommendation for the job of D.C. superintendent from former education secretary Shirley Hufstedler.

McKenzie has held several positions in the city school, including deputy suprintendent for educational programs and services, special assistant to the superintendent and acting deputy superintendent for instruction.

She started her career in 1957 as a social studies teacher in a Baltimore junior high school. She then taught social studies at Kelly Miller junior high school in Northwest Washington from 1960 to 1955 and was a teacher of history, government and sociology as well as a counselor at Roosevelt High School between 1965 and 1967.

She is one of six children, and a 1952 gradute of Dunbar High School here.

She also graduated from D.C. Teachers College in 1956 with a major in history and a minor in geography. She received an MA in history from Howard University in 1957. She took courses for a PhD in history at American University as well as various courses in administration at George Washington University and Catholic University.

McKenzie inherits a system that is facing all the problems common to many large unban systems -- a shrinking budget, declining enrollment, loss of teachers and increased crime in the schools.

But she will also take over when student achievement is slowing making gains after years of virtually no progress. Under Reed's direction, there was an increased emphasis on improving academic standards: a new academic high school for college-bound students is planned for the fall; the system has introduced new, stiffer standards for promotion in the elementary school; requirements for both junior high and high school graduation have been stiffened.

As Guines did, McKenzie will walk in the shadow of the enormously popular Reed, who abruptly resigned in December over repeated conflicts with the school board. She will be the fifth superintendent since 1967 and the second woman to hold the job.

After McKenzie was selected, Guiness, in a brief speech from the dais he shares with board members when they are voting, thanked them for selecting him in an acting capacity and commemded them on their choice of McKenzie.

The two associate superintendents who had also applied for the superintendency, Reuben G. Pierce and Andrew E. Jenkins, also praised McKenzie and vowed to work closely with her.