Parametric Inc., one of the largest minority-owned engineering and construction management firms, has elected Marshall A. Isler president of the Washington-based firm.

Isler was executive vice president of the firm. Before joining Parametric, Isler served in a variety of engineering management positions, including associate director of the National Engineering Laboratory at the National Bureau of Standards.

Vary T. Coates has joined the engineering and environmental consulting form of Dames & Moore as director of policy analysis and technology assessment.

Kenneth Gross has been named western sales manager for the monthly Mediatrend radio audience reports issued by Media Statistics Inc. of Silver Spring.

Stanley H. Gitelson has been elected 1980 president of the Greater Metropolitan Washington chapter of the Institute of Real Estate Management.

Robert W. Clyde has joined Acacia Mutual Life Insurance Co. as one of three marketing vice presidents directing the firm's nationwide operations.

Wilmer L. Tinley, Jr. has been appointed senior vice president and comptroller for the Central National Bank of Maryland.

Software AG of North America Inc., a Reston-based firm, announced these promotions: Kenneth D. Rardin, executive vice president; Edward J. Forman, vice president of technical operations; Steve Greaves, vice president of development. In addition, Software named Colin Moore to head the consulting division.

Dr. Paul M. Friedman has been named manager of the analytical and physical chemistry laboratory of Biospherics Inc.

Rex M. Phares, chairman of the board of Jetco Inc. and president of Transportation Commerical Factors Inc., has been elected to the board of directors of the Northern Virginia Bank.

Magnus T. Monson Jr. has been appointed commercial development manager for the Southern Railway System.

William A. Lubbers has been nominated by President Carter to serve a four-year term as general counsel of the National Labor Relations Board.

Carmel J. Cammaroto has been appointed vice president for marketing of Ginns Business Furniture and Interiors.

Terry Hourigan has been named vice president for programming, Frank J. Murphy III has been named vice president for station realtionss and Bruce Goodman has been named vice president and general counsel for the Mutual Broadcasting System.

Timothy J. Good has been appointed president and chief executive officer of Town & Country Mortgage & Investment Corp.

Carmen Kinsey has been named catering sales manager and Roman Adair Holton has been named assistant sales manager for The Washington Hilton.