According to a recent study:
"Men could work between 55 and 60 hours per week before their cognitive function dropped lower than if they were working no hours at all. For women, the number of working hours that produced the same result was between 45 and 50"
So when you hear the misleading statistic that women are only paid 77 cents of what men are paid, it is absolutely the way it should be. 60 hours that men can work translates into 46 hours that women can work. 60*.77=46
Of course, it's not what happens in the real world: men and women are paid the same for the same job. But women provide 77 percent less. The next time someone quotes that statistic, fire back this study.