 Smallest range using 36.42g/dm3 of HCl = 29.0 – 27.0  average= 28.0  29.0-28.0 = 1.0 and 28.0-27.0 = 1.0  28.0 + or – 1.5  this is a % error of +- (1.0/28.0)*100 = (0.03571428571)*100 = 3.571428571 = 3.6% so the mean reading is 28.0 +- 3.6% I don't know what it means and how I can link to my reliability of my results and confidence