Probabilites: expected value and variance

[XanderLeaDaren]

Problem you'd like to fix

Get both the mean / expected value (fr: espérance) and the variance of the available probability distributions.

Describe the solution you'd like

There is enough space in the “grey title bar” for each distribution to display the expected value and variance.

Screenshots

Left: actual / Right: proposition

Describe alternatives you've considered

Creating a Python script for each of the probability distributions: · binomial E = n×p, V = n×p×(1-p) · uniform E = ½(a+b), V = 1/12 × (b-a)² and so on…

[Ecco]

That's an interesting idea, and an enhancement definitely worse considering!

I'm not a huge fan of the suggested solution though, for several reasons:

• We try and avoid using abbreviations as much as possible.
• The reason we put "λ = 2" in the navigation is because that's what the user entered to get to this screen (so entering lambda=2 is part of the navigation). Putting a result there doesn't make much sense in my opinion.

We definitely could find some place on the screen to show this information though!

• The expected value might be drawn directly onto the chart (like a vertical line)?
• Or we could make the whole chart a bit less tall and put those values as a legend below the chart?
• Or we could make use of some blank areas of the chart and simply draw it there.

[XanderLeaDaren]

Yes, I wondered where to put the info, too.

Another place I thought of is in the first menu (see below), since E(X) and V(X) only need the distribution parameters to be calculated. This would not require changing the chart design, which is both elegant and useful, if I may.

As for abbreviations, E and V are both widely used notations for expected value and variance, and taught this way, at least in the French curriculum.

[artaxxx]

Thanks for the suggestion! I think it should appear in the last view (chart) because this is the view about the analysis of the distribution:

• 1 : type of distribution
• 2 : definition of the distribution
• 3 : analysis and results

So in terms of consistency, it should be better to display them on the last one. Maybe in a legend as @Ecco suggested.

[XanderLeaDaren]

Not found in Beta 17.0.0 – whereas assigned to Version 17 milestone. Any news?

[artaxxx]

We did not have time to design this feature in version 17