1. The problem statement, all variables and given/known data I am unsure how to do uncertainties for my lab experiment. For example, we are suppose to estimate or guess the uncertainty for like the time and measurements.. Is there any general rule for proper guessing? Then I am unsure on what to do with the uncertainties in math operations. I get confused between the uncertainty and standard deviation, as in... which i should use? 2. Relevant equations For example, I have t=0.123 and the uncertainty of the instrument is probably 0.001. and i have a distance of .5m and i dont know the uncertainty(this part we guess on?).. probably 0.00005m. when what does the uncertainty become when you divide the distance over time? I think you are suppose to do sqrt( .001^2 + .00005^2) but that gives such a small number it doesnt make much sense. and if i had velocity at this time. would my best estimate value be the calculated velocity? or the average of the calculated velocities? Because I am suppose to find the velocity at this time with its uncertainty. the template shows the uncertainty with delta v, and i thought delta meant the standard deviation.. so would that mean the delta v for all the trials i have done be the same if it were the standard deviation? Any help would be greatly appreciated.