"You have to look at who their groups are and what fields these women are in ... because from my understanding, African-American women are earning less [in most fields]," she said.

Gault said black women statistically work more than a month of additional full-time longer than white women do and are less likely to take long leaves for childbirth.

Also, black women contribute larger portions to their family's income than white women.

However, James Elliott, director of human resources at Penn State, said this might not be true among Penn State employees.

Elliott said Penn State employees all work overtime based on the demands of their specific job, and he has not noticed any difference among the amount of overtime based on race.

"Maybe globally they found this to be the case, but I would be amazed if they found that to be true on the Penn State campus," he said.

"Some people feel financially they need to come back earlier after a leave, but I haven't noticed any difference based on natural origin or race," Elliot added.

Gault said that although black women make more money yearly, their salaries are typically lower than white women.

"If you take all workers together, African-American women earn more because they are working more," she said.

"But if you compare apples to apples, and compare African-American women with other workers who are working the same amount, then African-American women are earning less," Gault added.

Census Bureau spokesman Robert Bernstein said Hispanic women, who have lower earnings, are also included in the white demographic, and if the earnings of only non-Hispanic whites and black women were compared they would be the same.

The study showed men are still earning the most money out of all groups.

David Baker, professor of education and sociology, said men in top positions might be preventing women from earning comparable salaries. But as women become more aware of discrimination, this is becoming less of a problem, he said.

"Although discrimination exists, the demands of family and kids is the biggest factor," Baker added. "The glass ceiling certainly happens in high-end jobs, but whether or not it happens enough to affect the statistic, I don't know."

Baker said that he thinks the most prevalent reason men are earning more yearly is because there are a lot of women that put their families before their occupations.

"Some women are stepping out of their career for child rearing," he said. "It makes it more difficult [to earn high salaries] when exiting and entering the work force."