Sir i am stuck on this question

Q2: A- a sample of 14 students who passed an examination. They got the grades following (out of 20): {16, 18, 9, 11, 7, 11, 14, 12, 12, 16, 14, 9, 13, 6}. 1) Create an array that contains: . Sample (E). . Statistical units (i). . Variable {X}. . Values {x1, x2,..., xh}. . Numbers associated with each value {n 1 , n 2 ,..., nb}. 2) Create a graph of represents the grades by the values and the numbers associated with each value. 3) Calculate the variance