The first in a series of expected federal crack-downs on sex discrimination at colleges and universities occurred this week when the University of Michigan agreed to pay back wages to "any woman paid less than any man in comparable job categories."

Rebates will extend back to October 1968, in line with an agreement with the Department of Health, Education, and Welfare. HEW is currently investigating eleven schools for sex discrimination. Michigan is the first to receive a list of demands for specific changes.

Harvard is among the universities under investigation by the HEW.

The Women's Equity Action League (WEAL), a Washington-based group whose members include several Congresswomen, has put pressure on HEW to enforce a 1968 government order prohibiting sex discrimination. WEAL has filed charges with the HEW against 200 colleges and universities.

HEW began its investigation of Michigan last August, and "found no evidence of discrimination." After protests by WEAL, they reopened the probe, and this October, HEW presented Michigan with a set of demands for an "affirmative action plan" which included paying reparations to women.

The university made an unacceptable compromise proposal on Dec. 15 and HEW placed contract bans on $4 million worth of government contracts. The bans were lifted this week when Michigan agreed to HEW's demands.

When HEW investigators showed up at Harvard last March, the University at first refused to open its files to them. A reported $3 million in government contracts was temporarily held up.

Harvard then opened the files to HEW, and negotiations are still going on. A statement made by HEW officials on Dec. 1 claimed that the study of Harvard's practices will be completed "very soon." The investigation of the University of Michigan took only three months.

Michigan officials, terming HEW's demands "totally unreasonable," have circulated copies to other involved university administrations to gain support.

President Pusey received such a letter from Michigan but said that there is no organized university movement to prevent HEW from exacting its demands.

The demands placed by HEW on Michigan have yet to be officially released. According to the Nov. 20 issue of Science magazine, the demands include:

payment of back wages to female employees who have received lower pay than men in comparable job categories over the last two years;

achievement of equal salaries for men and women in the same category:

achievement of a ratio of female employment in academic positions equivalent to availability of qualified female applicants;

assurance of the elimination of separate male and female job classifications.

HEW's requirements for an affirmative action plan differ for each university, according to the nature of complaints filed by WEAL and the findings of HEW's subsequent investigation.