In a study of 826 women, 28 percent began menstruating during the four days around the new moon, whereas no more than 13 percent did so during any other four day period.
Woman usually get their periods at the same time.
mnli hypothesis: Woman usually get their periods at the same time. premise: In a study of 826 women, 28 percent began menstruating during the four days around the new moon, whereas no more than 13 percent did so during any other four day period.