Hi guys, My friend was asked the following question in an interview: There are 3 weight scales and a 10kg weight. You weigh the 10kg on each scale 5 times (total of 15 measurements for the 3 scales), each measurement is a bit off the 10kg mark (lets say the first scale shows: 11kg, 9.4kg, 12.1kg, 10.6kg. 10.2kg). You are suppose to choose the criteria of which scales is more accurate. Why is it better to use standard deviation instead of the medium or average? How do you create a calibration formula for the scale? Thanks!