posted by .

We're actually learning propigation of error in my chem class, but it seems to be used equally as much in Physics/Stats.

My teacher showed us two methods of doing it:

REAL Method (Addition/Subtraction):
square root[(error absolute 1)^2 + (error absolute 2)^2 +...(error absolute n)^2]

"Our School's" Method:
(Error absolute 1) + (Error absolute 2) +... (error absolute n)

Real Method (Mult/Div)
square root[(error % relative 1)^2 + (error % relative 2)^2 + ... (error % relative n)^2]

"Our" Method:
(Error % rel 1) + (error % rel 2) + ... (error % rel n)

He also has written
Absolute error/magnitude x 100 = Error % relative?

After doing most of a problem out, we have this:

1.0(sub 8) +/- 1(sub 8) %
We divide that by 100 to get rid of the percent and get
1.0(sub 8) +/- .18 REL error

I'm not sure what to do next, but we end up getting
1.0(sub 8) +/- 0.1(sub 9) which gives us an answer of 1.1 +/- .2 g/mL

How do I get from relative error to absolute error? In other words, what happened between the part where I got the relative error, and the part I don't know how to do?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Propagating error

    Find the absolute and percent relative error for each calc. b) 81.5 (+/- 0.5) x 40.2 (+/- 0.2)/ 21.8 (+/- 0.2) my answer for absolute error was 150. +/- 200, which is outrageous. Can someone show how they would do it so I can compare …
  2. Math

    a square + b square = 80 ft (c Square) Through trial and error I can tell you that 6 squared (36) and 12 squared (44)are what you're solving for, but I just used trial and error to figure it out. 12 square is 144, not 44 a and b can …
  3. Chemistry

    How do you find Absolute error and how do you find relative error?
  4. Calculus

    Estimate delta(x) using the Linear Approximation and use a calculator to compute both the error and the percentage error. f(x)=cosx a=(pi/4) delta(x)=.06 delta(x)= ______ i got this part and it's -.04242 The error in Linear Approximation …
  5. College Chem

    how do i figure out the percentage error , as well as the absolute error of a) (10.00+/- .02)mL x .42 mol/L b) (10.00 +/- .02)mL + (10.00 +/- .02)mL
  6. Using Matlab

    imagine you have a simple calculator that can only do addition,subtraction,multiplication and division. show how you can still use it to calculate the cube root of a given number, ie a^1/3, as follows: a)show that newton raphsons method …
  7. university physics

    Derive absolute error in equations: 1)Derive absolute error in (e/m) e/m= 2V/B^2*R^2 2)Derive absolute error in B B=8uN(Inet)/square root 125a
  8. Statistics

    An opinion poll asks a random sample of 100 college seniors how they view their job prospects. In all, 53 say "Good." The 95% confidence interval has a margin of error of 9.9%. The sample used actually included 130 college seniors …
  9. Physics

    Explain how you would determine how much error there is between a vector addition and the real results.
  10. chem/stats

    Find the absolute error for the answer of the following equation: square root of 3.24 plus-minus 0.08 end root equal 1.80 plus-minus ?

More Similar Questions