Find the range, the quartiles and the IQR
Marks (out of 50) scored on a short class quiz are given below
15 marks, 18 marks, 19 marks, 21 marks, 24 marks, 34 marks, 41 marks
Use the median-of-halves convention: order all observations, retaining repeats. If the number of observations is odd, omit only the middle observation from both halves. Q1 and Q3 are the medians of the lower and upper halves