Remove bar chart as permissible representation for aggregates

[alexsb]

Bar charts are not suitable to represent the median of a distribution due to within-the bar bias. Remove this option (add a dot plot instead, will create a separate ticket).

Here is an example for the matrix:

Here is an example for a group of a numerical column:

[sgratzl]

depends how you see it. if it should a representation of an array I agree, if it should be an representation of a projection of an array to a single value, I disagree.

[mstreit]

@sgratzl, I don't understand what you mean. What is your suggestion?

[sgratzl]

I mean it is our decision how you wanna see and sell it. Both are valid options. I just wanted to bring up the other aspect, too.

[mstreit]

OK. If we remove the single bar from the vis option, it also means that the column cannot be combined/stacked with other numerical columns.

[sgratzl]

yes-ish. since it is based on the projection of 1D to 0D as mentioned before.

[alexsb]

I don't agree. Even if you have a projection into a lower space, you represent an aggregate value in some way. That aggregate has uncertainty and variability associated with it, so the within-the-bar bias still applies.

See http://www.tandfonline.com/doi/pdf/10.1080/00031305.2016.1141706

I think for stacking aggregates, we should think of something fancier?

[mstreit]

I get your point, but in Ordino users heavily use the stacking of columns where at least one is an aggregate.
Any ideas how 'something fancier' could look like?

[alexsb]

Something like this:

Basics of a box plot, the darker areas show the possible positions of the mean for B and C.

Or this:

The black violin plots are the distribution of only that variable, the red ones show cumulative uncertainty.

[sgratzl]

-> should be moved to #201

[mstreit]

solved with #362 and #401.