Kuartil bawah 6,7,7,8,8,8,9,9,10,11,12,13

Data 6 7 7 8 8 8 9 9 10 11 12 13
kuartil bawah(Q1)=7
median(Q2)=8+9/2=17/2=8,5
kuartil atas(Q3)=11