Statistics: add scaling functionality

[mgovers]

This is a cherry-pick of the statistics functionality in #951 .

It adds statistics::scale functions next to the already present statistics::combine functions

Do not merge before #947 and #954 are merged

[figueroa1395]

These set of scale function, and their tests, were taken literally from #951, right?

One minor nitpick, could you add an in-code comment above the scale functions implementation with the permalink to the issue where this calculations are done, just for reference. Or better yet, also shortly add in-code from where you start and where you get in the variance scale specifically? Just so that we see where does the calculations come from once we have forgotten about this.

Oh, I will approve after possible merge conflicts (as stated in the introduction of the PR) are resolved.

[mgovers]

These set of scale function, and their tests, were taken literally from #951, right?

yes

One minor nitpick, could you add an in-code comment above the scale functions implementation with the permalink to the issue where this calculations are done, just for reference. Or better yet, also shortly add in-code from where you start and where you get in the variance scale specifically? Just so that we see where does the calculations come from once we have forgotten about this.

what do you mean?

Oh, I will approve after possible merge conflicts (as stated in the introduction of the PR) are resolved.

no merge conflicts because i had already resolved those

[figueroa1395]

what do you mean?

As in, as taken from #547, just add:

$$\begin{align} var = \sqrt{\sigma_r^2 + \sigma_i^2} \end{align}$$

but for the actual variance scaling, above is just for demonstration of what I mean. So add an in-code comment with the formula.

no merge conflicts because i had already resolved those

Yup, realized after commenting.

The base branch was changed.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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