The tensile strength in MP3 (mega pascals) measured for a random sample of 20 pieces of diecast aluminium is displayed in the following stemandIeaf plot: 17 007 leaf unit 2 1 18 3 19 47 20 125 21 22 23 23 04448 24 014 25 26 2 The sample mean and standard deviation are: 5: = 215.05 3 = 27.19225 Assuming that the tensile strength measurements are Normally distributed, what is the width (u pper limit minus lower limit} of the 90% condence interval for the population standard deviation? Select one: 0 a. 21.028 0 b. 11.20? 0 c. 15.676 0 d. 12.000 0 e. 20.145