How to calculate Uncertainty in chemistry?

Book A Demo Class

Calculating Uncertainty is not an easy process. People find it challenging to estimate Uncertainty. This is why we have picked up the topic here so that you will get to know the procedure that will help you calculate it easily. All you need to do is focus on an eight-step process appropriately, and you will never find it difficult to calculate it quickly and adequately. 

How to calculate Uncertainty?

Specify the measurement process

Before getting into the calculation process, it is essential to have a plan. The planning is undoubtedly an excellent start to get the appropriate outcomes. First of all, you need to identify the measurement process. This will help you in uncertainty analysis and focus your kind attention on what matters the most.

How to specify the Measurement process?

Follow the below-mentioned instructions to specify the measurement process:

Select the measurement function to evaluate
Select the procedure or measurement method to be used
Select the equipment to be used
Select the desired range of measurement function

Determine the test points to be evaluated.

Identify and characterize Uncertainty resources.

Now that you have figured out the measurement processes to be evaluated, you need to identify the factors influencing Uncertainty in measurement results. However, this process is not an easy one, so be patient while working. 

Finding Uncertainty sources

Finding uncertainty resources can be complicated and require a lot of time and effort. This stage is considered the most time-consuming process while evaluating the uncertainty measurement. 

How to find Uncertainty sources

Follow the below-mentioned steps to find uncertainty sources

Evaluate measurement process, calibration procedure, or test method

Evaluate measurement equations
Evaluate reference standards, reagents, and equipment
Identify minimum required uncertainty resources
Research for various information sources
Consult an expert

Quantify Uncertainty resources

Before moving the calculation of measurement uncertainty, you need first to determine each contributing factor’s magnitude. To attain this, you need to perform such data analysis and reduction.

How to Quantify Uncertainty?

Follow the below-mentioned steps to quantify the Uncertainty

Collect data and information

Select the correct data after appropriate evaluation
Data analysis
Quantify Uncertainty components.

Characterize Uncertainty resources

Characterize each factor by a probability distribution and uncertainty type. 

How to characterize Uncertainty sources?

Follow the procedure to characterize your uncertainty sources

Categorize each uncertainty source: Type A or Type B
Assign a probability distribution to each component

Convert Uncertainties to standard deviations

After the probability distribution, identify the equation required to convert each uncertainty contributor to a standard deviation equivalent. This will help to reduce the uncertainty source to a 1-sigma level. 

How to convert Uncertainty to standard deviations?

Follow the below-mentioned steps to convert uncertainty components to standard deviations

Assign a probability distribution to each uncertainty sources
Find the divisor for the selected probability distribution
Divide each uncertainty source by respective divisor.

Calculate Combined Uncertainty

After converting the uncertainty sources, it is time to calculate combined Uncertainty by the root sum of squares (RSS) method. 

How to calculate the combined Uncertainty?

Follow the below-mentioned steps to calculate combined Uncertainty

Square each uncertainty component’s value

Add together all results obtained in the first step
Calculate the square root of results obtained in step 2

Calculate expanded Uncertainty

You have reached the phase where you are almost done with the uncertainty estimation. 

How to calculate the expanded Uncertainty?

Follow the steps to calculate expanded Uncertainty

Calculate combined Uncertainty
Calculate Freedom’s effective degrees
Select or Find a coverage factor (k)
Multiply combined Uncertainty by a coverage factor

Evaluate your Uncertainty budget

Now that you are done with the calculation of expanded Uncertainty, it is the best time to evaluate the uncertainty estimate for appropriateness. Ensure that your measurement uncertainty estimate appropriately represents the measurement process and is not under or over-estimated. 