A new study by the National Association of Women Business Owners indicates that statistics on the economic strength of businesses owned by women may have been seriously understated by earlier surveys.

The study, which was funded by the Small Business Administration, includes national figures on women who co-own corporations or partnerships. Other current studies have based their results mainly on Internal Revenue Service tax data on sole proprietorships, or single-owner businesses, said NAWBO President Virginia Littlejohn.

The 766 women respondents to NAWBO's survey reported average yearly company revenue of $425,000. Sixty percent of the respondents owned partnerships or corporations.

By contrast, an annual report on the state of small business released by the IRS last March found that the average yearly revenue for sole proprietorships owned by women was $13,333.33. The IRS study, however, included data on millions of women-owned businesses.

Littlejohn said NAWBO initiated the study because it suspected that most of the recent reports on women business owners were inaccurate. Littlejohn said she hoped to set a precedent for future studies of this kind.

The survey, which was mailed in questionnaire form to the 1,287 women who belonged to NAWBO as of last January, found that the respondents' businesses have combined total revenue of more than $500 million a year. The companies have an average of 11 full-time employes with an additional 14 part-time or contractual workers. The study also found that 75 percent of the respondents owned companies with gross annual sales of more than $80,000.

According to the findings, the women surveyed tended to be "fiscally conservative but moderate on social issues." The reason for this, Littlejohn said, is that women business owners are concerned about the economy and how it effects their firms, but also realize that there is inequality in the work place and want to see women participate in the economic mainstream.

Those surveyed were evenly divided between Democrats and Republicans. Most of the women owned professional service companies such as consulting firms and law firms, but others owned such nontraditional businesses as manufacturing firms, trucking agencies and robotics companies.

NAWBO currently has 1,800 members nationwide, including 200 in Washington. The association is working on the Women's Business Ownership Act of 1985, an omnibus bill that they hope will encourage the development of programs to remove existing credit barriers and improve data collection on women businesses owners. NAWBO also has received a $5,000 grant from Sears & Roebuck Inc. for data collection improvements. TRADE

The American Chemical Society, a Washington-based organization for professional chemists and chemical engineers, has reelected Paul V. Smith chairman. Smith is manager of education and professional society relations at Exxon Research & Engineering Co. Warren D. Niederhauser, a past president of the ACS, was recently named chairman-elect of the Council of Scientific Society Presidents. He will remain on ACS's board of directors. Other newly elected ACS officers were: Ellis K. Fields, a research consultant at Amoco Chemicals Corp., president; and George C. Pimentel, director of the biodynamics lab at the University of California, president-elect.

John Mancini, former executive director of the Foundation for Public Affairs, has left that association to become political support manager for the Washington-based American Electronics Association.

Nancy Chistolini, vice president and director of creative merchandising at Hecht's department stores, will join the board of The Fashion Group Inc., an international association of women fashion-industry executives. PROFESSIONAL

The National Association of Securities Dealers Inc. has elected Patrick C. Ryan to its District 10 Business Conduct Committee for a three-year term. Ryan is senior vice president, director and manager of the trading department at Johnston, Lemon & Co. The committee enforces NASD and federal trading rules for the District, Maryland, Virginia and North Carolina.

Thomas G. Moore, president and chief executive officer at Central National Bank of Maryland, has been elected a member of the advisory board of the Community Bankers Council of the American Bankers Association. The council comprises CEOs from banks with assets of less than $150 million. The 190 members from all 50 states meet twice a year to discuss government relations issues concerning the banking industry. Council members also serve as representatives to ABA conferences throughout the year.