Other pages in this series (5)
A3
Revision size relative to the previous uncertainty
Distribution of revision size divided by the previous recommendation's uncertainty
Takeaway
- The median of |z_old|, revision size over previous uncertainty, is 0.24: most revisions moved by about a quarter of the previous range.
- Definition
- For the same revisions as A2, (new value − old value) ÷ old uncertainty. An absolute value above 1 means the revision left the previous range.
- Formula
- z_old = (x_new − x_old) / U_old
- Denominator
- The same 204 revisions as A2.
- How to read it
- The median |z_old| is 0.24: most revisions moved by about a quarter of the previous range (U). 82% have |z_old| ≤ 0.5.
- Caveats
- The denominator U is an expanded range, so this z is not on the same scale as the z of the physical-constants chapter (divided by a standard uncertainty).
| Symbol | Previous | New | z_old | Ranges disjoint |
|---|---|---|---|---|
| Th | 2005: 232.038 06(2) | 2013: 232.0377(4) | −18.000 | |
| Zn | 2001: 65.409(4) | 2007: 65.38(2) | −7.250 | yes |
| C | 1961: 12.011 15(5) | 1969: 12.011(1) | −3.000 | |
| H | 1961: 1.007 97(1) | 1969: 1.0080(3) | 3.000 | |
| Pt | 1995: 195.078(2) | 2005: 195.084(9) | 3.000 | |
| Br | 1961: 79.909(2) | 1965: 79.904(1) | −2.500 | yes |
| Bi | 1969: 208.9806(1) | 1971: 208.9804(1) | −2.000 | |
| Yb | 2007: 173.054(5) | 2015: 173.045(10) | −1.800 | |
| Ge | 1985: 72.61(2) | 1999: 72.64(1) | 1.500 | |
| S | 1961: 32.064(3) | 1969: 32.06(1) | −1.333 | |
| K | 1969: 39.102(3) | 1971: 39.098(3) | −1.333 | |
| Lu | 2007: 174.9668(1) | 2024: 174.966 69(5) | −1.100 | |
| Cs | 1969: 132.9055(1) | 1971: 132.9054(1) | −1.000 | |
| Ho | 1969: 164.9303(1) | 1971: 164.9304(1) | 1.000 | |
| Cd | 1969: 112.40(1) | 1975: 112.41(1) | 1.000 | |
| Ni | 1973: 58.70(1) | 1979: 58.69(1) | −1.000 | |
| Xe | 1969: 131.30(1) | 1979: 131.29(3) | −1.000 | |
| Zn | 1971: 65.38(1) | 1983: 65.39(2) | 1.000 | |
| Sb | 1989: 121.757(3) | 1993: 121.760(1) | 1.000 | |
| Bi | 1995: 208.980 38(2) | 2005: 208.980 40(1) | 1.000 |
Source: Standard atomic weights © IUPAC/CIAAW 2016–2024. Commission on Isotopic Abundances and Atomic Weights, Historical changes of standard atomic weights (compiled by J. Meija), https://www.ciaaw.org/historical-atomic-weights.htm