1. Precisions of Adjusted Quantities

2. Introduction
After a least squares adjustment, the covariance matrix for the computed unknowns can be computed from N-1
Then apply GLOPOV to obtain precisions of indirectly determined quantities

3. Covariance Matrix Population Sample
The standard deviation for computed unknown, xi is:

4. Example – Leveling: Unweighted

5. Example - Continued

6. Covariance of Computed Values

7. Numerical Example

8. Example - Continued

9. Example - Continued

10. Example - Continued

11. Final Summary

12. Computing Standard Deviations for Observations That Were Not Made
Say we wanted the standard deviation for the elevation difference from A to C. The equation is:
C – A = 1.05
Note that only the 4 corner values from N-1 were used.

13. Summary
For a computed unknown, the standard deviation is S0 times the square root of the corresponding diagonal term from N-1
For functions of unknowns (observed or not) we need the corresponding variances and covariances – then apply GLOPOV (along with standard deviation of unit weight)