# Self-assessments for: Network Quality Assessment by Measures of Precision

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These self-assessment problems accompany the mini course Network Quality Assessment by Measures of Precision.

## Problem 1

a) What is the difference between a local and global measure of precision? b) Provide two examples of each, explaining what they are.

## Problem 2

a) Using the network in Lab 3, provide an example of one local and one global measure of precision. You don’t need to modify or add this to any code you had before. Rather, do / provide the calculations any way you like using the or matrix as input. Provide all of the matrix elements themselves in your answer, as well as your results in each of the examples. b) Provide some useful interpretation of the results of a).

## Problem 3

What’s the importance of “diagonalizing” a variance-covariance matrix?

## Problem 4

What equations (that we’d seen before in the context of the error ellipse) do you use for diagonalizing a 2×2 variance-covariance matrix?

## Problem 5

If the following is a plot of some position errors in the east and north directions, then what sign does the covariance have, i.e. would it be positive or negative?

## Problem 6

a) Explain the importance of . b) If, after carrying out an adjustment, you determine to be different from by a statistically significant amount then what do you do? To what outputs of the adjustment does it apply and how in each case?

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