>>12046058ok I'll bite
the measurement error in chemistry is relative
for example
if your result is 12.31337 mg/kg and the method error is 1%, it means means it's 12.3 +- 0.1 mg/kg
you can measure the same sample 3 times and get results like 12.36969, 12.31488 and 12.30420
2 significant numbers are enough for basic methods with STD~10%
3-4 significant numbers are typical for instrumental methods and skilled chemists
more than 4 significant numbers is usually just an idiot writing down whatever the calculator spits out at him
