Formula Generator | Excel

Expanded Uncertainty Calculation in Excel

This guide details the process of calculating expanded uncertainty for pressure measurements in Excel, using standard deviation and coverage factors for accurate results compared to a reference manometer.

Prompt

Answer

Calculating Expanded Uncertainty in Excel

Overview

This document outlines the steps to create an Excel spreadsheet that calculates expanded uncertainty for 8 pressure measurements compared to a standard manometer. The formula will take into account the standard deviation of the measurements and the coverage factor.

Required Inputs

Pressure Measurements: Eight individual measurements (in appropriate units).
Reference Pressure: Standard manometer value.
Standard Deviation: Calculated from the pressure measurements.
Coverage Factor (k): Typically determined based on the desired confidence level (e.g., k=2 for approximately 95% confidence).

Steps to Create the Excel Spreadsheet

Step 1: Input the Data

Open Excel and create a new spreadsheet.
In column A (A2 to A9), enter your 8 pressure measurements.
In cell B1, enter the reference pressure (standard manometer reading).

Step 2: Calculate Mean of the Measurements

In cell C1, enter the following formula to calculate the mean of the pressure measurements:

=AVERAGE(A2:A9)

Step 3: Calculate Standard Deviation

In cell C2, enter the following formula to calculate the standard deviation:

=STDEV.S(A2:A9)

Step 4: Calculate the Expanded Uncertainty

To calculate expanded uncertainty in cell D1, use the following formula. Assume a coverage factor of k=2:

=C2 * 2

Step 5: Calculate the Difference Between Measurements and Reference

In column E (E2 to E9), calculate the difference of each measurement from the standard manometer's reading:

=A2 - $B$1 (drag this formula down from E2 to E9)

Step 6: Finalize the Table

Label your columns as follows:
- A1: "Pressure Measurements"
- B1: "Reference Pressure"
- C1: "Mean"
- C2: "Standard Deviation"
- D1: "Expanded Uncertainty"
- E1: "Difference from Standard"

Example

Assuming the following sample data for the 8 measurements:

A (Pressure Measurements)
100.1
99.8
100.3
100.0
99.9
100.2
100.1
99.7

Reference Pressure

In B1, the reference pressure could be 100.0.

Calculations

Mean (C1) = 100.075
Standard Deviation (C2) = 0.231
Expanded Uncertainty (D1) = 0.462 (2 * Standard Deviation)

Results Table

A	B	C	D	E
Pressure Measurements	Reference Pressure	Mean	Expanded Uncertainty	Difference from Standard
100.1	100.0	100.075	0.462	0.1
99.8				-0.2
100.3				0.3
100.0				0.0
99.9				-0.1
100.2				0.2
100.1				0.1
99.7				-0.3

Conclusion

This Excel model provides a straightforward approach for calculating the expanded uncertainty of pressure measurements against a standard manometer. Ensure that the coverage factor aligns with the confidence level you require for your analysis.

For anyone looking to enhance their Excel skills further, consider exploring the Enterprise DNA Platform for specialized courses and resources.