How Do I Combine Measurement Uncertainties?

[lavster]

i have a measurement which has random uncertainty of 0.02 and scale reading 0.01. how do i combine these uncertainties - add in quadrature the percentage uncertainty or the absolute uncertainty? and does this give the percentage uncertainty or the absolute uncertainty of my measurement?

thanks

 

[mathman]

If both uncertainties are random and independent, add the squares of the absolute uncertainties and take the square root.