Which of these is an example of an ideological interest group?

Asociologist chose 300 students at random from each of two schools and asked each student how many siblings he or she has . the result are shown in the table below. there are a total of 2,400 students at lincoln school and 3,300 students at washington school .what is the median number of siblings for all the students surveyed ? a)0b)1c)2d)3