Reply to thread

Message

<blockquote data-quote="swimfreak26" data-source="post: 1231753" data-attributes="member: 544365">The mean of any set of numbers is just the sum of that set, divided by the quantity of numbers you have.You&#039;re most likely going to have multiple errors in a system, and you basically just add them up and divide by the number of different errors you had. You&#039;ll notice in general, that some of the errors will essentially disappear because their size is insignificant in comparison to others.Now, there is a slight issue that you may not be aware of though. The question MAY be asking about the uncertainty, which is different all together. The uncertainty in an addition/subtraction equation (used to find your final variable) is the uncertainty (error) in each, added together...unless the measurements are independent of one another (most cases), where now the uncertainty is equal to the sqrt(u1^2 + u2^2 + ...).If you are asked to do this on examples where your variable is calculated by multiplication/division (i.e.&nbsp; p = mv) then you have to add the fractional uncertainties in quadrature and multiply by the calculated value of the calculated quantity. So (I will use &quot;d&quot; for the ucertainty symbol here)....dp = p * sqrt( (dm/m)^2 + (dv/v)^2 )I think I gave you way too much information, and probably the first line is all you need, however this stuff will come in later I guarantee it, very important in measurements that you make in a lab.</blockquote>

[QUOTE="swimfreak26, post: 1231753, member: 544365"] The mean of any set of numbers is just the sum of that set, divided by the quantity of numbers you have. You're most likely going to have multiple errors in a system, and you basically just add them up and divide by the number of different errors you had. You'll notice in general, that some of the errors will essentially disappear because their size is insignificant in comparison to others. Now, there is a slight issue that you may not be aware of though. The question MAY be asking about the uncertainty, which is different all together. The uncertainty in an addition/subtraction equation (used to find your final variable) is the uncertainty (error) in each, added together...unless the measurements are independent of one another (most cases), where now the uncertainty is equal to the sqrt(u1^2 + u2^2 + ...). If you are asked to do this on examples where your variable is calculated by multiplication/division (i.e. p = mv) then you have to add the fractional uncertainties in quadrature and multiply by the calculated value of the calculated quantity. So (I will use "d" for the ucertainty symbol here).... dp = p * sqrt( (dm/m)^2 + (dv/v)^2 ) I think I gave you way too much information, and probably the first line is all you need, however this stuff will come in later I guarantee it, very important in measurements that you make in a lab. [/QUOTE]

Verification