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Calculate uncertainty

Hello Experts:

I need some assistance with applying a formula/equation (based on calculating "uncertainty".

As the saying goes "A picture is worth a thousand words", I've attached a spreadsheet that contains the following:

1. Calculation of sound in sea water (this is complete)
2. Reference to website that includes equations for "uncertainty"

Based on step #2, I need to calculate the value for uncertainty based on a) multiple inputs and b) single input.

Given the listed equations (on NIST's website), how to I calculate a) and b) in MS-Excel?

Thank you in advance,
EEH
Calculate-uncertainty.xlsx

ASKER CERTIFIED SOLUTION

Graham Mandeno

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ASKER

Graham:

How did you arrive at 4.591?

=2.05^2 = 4.2025... multiplying it by 0.5^2 doesn't give me the value either.

Would you be ok to send me your version of the spreadsheet w/ these calculations?

Thanks,
EEH

Graham Mandeno

Hi EEH (what's your real name, by the way? :)

Thanks for awarding the points. I'm puzzled because I posted a followup answer to your question 24 hours ago and it seems to have disappeared.

The 4.591 is the coefficient of the first non-constant term in the Mackenzie formula:

1448.96 + 4.591T - ...

As I understand the article on combined uncertainty, it is therefore the a1 in the term:
a1^2*u(x1)^2
and u(x1) is the uncertainty of T.

I don't have my own version of the spreadsheet, sorry. I just took a peek at your copy.

All the best,
Graham

ExpExchHelp

ASKER

Graham:

Thanks... appreciate the additional feedback. ;)

Cheers,
Tom