How Do Derivatives Estimate Measurement Errors?

In summary, the conversation discusses determining the error of a resistor with a value of 5K\Omega that was measured to be 4.8K\Omega. One approach to calculating the error is through simple percentage calculation, while another method involves using derivatives. However, the latter method may not be applicable in this case due to the discrete nature of the data.
  • #1
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Homework Statement


I have a resistor which has value written as [itex]5K\Omega[/itex] and I measured the value and it is [itex]4.8K\Omega[/itex]. I want to work out the error.


2. The attempt at a solution
I can use simple percentage calculation to get [itex]\frac{4800-5000}{5000} \times 100 = -4[/itex]% error but I've been told that derivative can also be used to calculate error, how would I go about doing that? :confused: Thanks in advance.
 
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  • #2
Determining % error using a derivative requires a continuous function that is derivable. Since the data is discrete and only two points are given a derivative in this case cannot be taken.
 
  • #3
I think you may be confusing percent error with expected error. As chrisk suggests, you need to have a theoretical function that depends continuously on various physical parameters, and then you take the derivative w.r.t. those parameters, and then multiply by the precision of those parameters (basically). This error estimation using derivatives is not a percent error, because it makes no assumption regarding what the result of the measurement should be.
 

What is Percentage Error Analysis?

Percentage Error Analysis is a method used to determine the accuracy of measured values by comparing them to the true or accepted value.

How is Percentage Error calculated?

Percentage Error is calculated by taking the absolute value of the difference between the measured value and the true value, dividing it by the true value, and then multiplying by 100%. This value represents the percentage difference between the measured and true values.

Why is Percentage Error Analysis important?

Percentage Error Analysis is important because it allows scientists to assess the accuracy of their experimental results. It also helps identify any sources of error in the experiment and can lead to improvements in future experiments.

What are the limitations of Percentage Error Analysis?

Percentage Error Analysis does not take into account the direction of the error, only the magnitude. It also assumes that the true value is known and may not be applicable in cases where there is no accepted value or the true value is constantly changing.

How can Percentage Error Analysis be used in real-world applications?

Percentage Error Analysis can be used in a variety of fields such as chemistry, physics, and engineering to evaluate the accuracy of measurements and experimental results. It can also be used to compare the performance of different methods or instruments used in data collection. Additionally, it can be used in quality control to ensure products meet certain standards of accuracy.

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