Basic Training 4th Annual ICP Conference

Rules for combining uncertainties

1. Addition and/or subtraction

2. Multiplication and/or division

! "#$% = ' ( . ( * = . + * + . * * + ⋯ = ) + / + ∗ 100 * + ) * / * ∗ 100 * + ⋯

! "#$% = ' (

) ( * = ) +* + ) ** + ⋯

Use absolute uncertainties

Use relative uncertainties

5. How to report uncertainty?

• Expanded uncertainty (U) ! = "# $%&' • k is the coverage factor • Confidence level

• Common reporting method ( ± ! • Must state coverage factor

• Distribution • # of values

• Useful to provide information about how the value was obtained