3.1.2 - Uncertainty Flashcards
Absolute uncertainty =
Resolution / 2
Fractional uncertainty =
Absolute uncertainty / measured value
Percentage uncertainty =
Absolute uncertainty / measured value x100
What do you do with the uncertainty when you add or subtract values?
Add the absolute uncertainties.
What do you do with uncertainty when multiplying values?
Add the percentage uncertainties.
What do you do with uncertainty when you divide values?
Add the percentage uncertainties.
If there are powers in the equation what do you do with uncertainty?
Multiply the percentage uncertainty by the power.
How do you estimate the uncertainty in the mean?
Range / 2
In what case should you ignore an anomalous result?
If it had a reason which could be identified it can be ignored.
When plotting what should you do with anomalous results?
Plot them but ignore them when the line of best fit is being decided.
When else should anomalous results be ignored?
When the results are expected to be the same.
When should anomalous results be included?
When there is no obvious error or expectation that the results should be the same.
On graphs how do you work out percentage uncertainty?
( (best gradient - worst gradient) / best gradient) x100
How else can you work out percentage uncertainty on a graph?
( (best y intercept - worst y intercept) / best y intercept) x 100
Why do we use error bars?
To indicate the maximum error and minimum error we could get.