Statistically speaking TB Yevamot11

When do the rabbis follow the majority? It depends upon the case before them. “When the Rabbis follow the majority, it is an evident majority (רוּבָּא דְּאִיתֵיהּ קַמַּן), which is extant and can be examined. For example, in a situation where a piece of meat is found in front of nine stores selling kosher meat and one store selling non-kosher meat, if it is not known from which store the meat came, it may be assumed that it came from one of the stores that sells kosher meat. And similarly, the Sanhedrin reaches its decisions by a majority vote of its members. But with regard to a non-evident majority (רוּבָּא דְּלֵיתֵיהּ קַמַּן), which is based solely upon general statistical information, such as the assertion that most women become pregnant and give birth, even the Rabbis do not follow the majority.” (Srfaia.org translation)

We learn that a legal presumption (חֲזָקָה) is not as significant in the decision-making process then as a majority (רֹב). “In the first clause of the mishna, the legal presumption is that this widow is obligated to enter into levirate marriage, but in a majority of cases she will actually be permitted to marry a man from the general public, because it is statistically probable that her rival wife had a child. A legal presumption is not as significant as a majority, meaning that the majority carries more weight than the presumption, and she should be permitted to marry immediately. But bring the minority who miscarry into consideration, and join this to the legal presumption, and it becomes similar to an even balance of half and half. Those who miscarry detract from the strength of the majority, causing it to be equal in legal significance to the legal presumption. Therefore, the ruling is that she shall not marry any man who is not her yavam and she shall not enter into levirate marriage either.” (Sefaria.org translation)

However if the legal presumption and the majority’s outcome would be the same, one does not have to take into consideration a possible minority’s outcome because that would be a minority of a minority (מִיעוּטָא דְמִיעוּטָא). “However, in the latter clause, the legal presumption is that the widow is permitted to marry a man from the general public, since her late husband had no brothers initially. And in a majority of cases her mother-in-law will not have had another son, and therefore the widow will actually be permitted to marry a man from the general public. Consequently, the possibility that her husband has a brother, necessitating levirate marriage, is not taken into account because it is a minority of a minority, i.e., it is a minority and it contradicts the legal presumption, and even Rabbi Meir is not concerned about a minority of a minority.”