nilai = 21 - 25 , 26-30, 31-35, 36-40, 41-45. frekuensi = 3 ,6, 14, 15,2 .hitunglah rata rata nya

jawab

∑f = 40

∑f.xi = 3(23) + 6(28) + 14(33) +15(38) + 2(43) = 1.335

X = ∑f. xi/ ∑f = 1.335/ 40 =

X= 33,875