Hi,
we have talked to each other and the effect was due to having set the x-variable as a continuous one, and this continuous one had many different values spread over a wide range. Taking it nominal had the well known wider appearance, although (as you can see below) the more levels you have the thinner the boxes get. Using the box plots in the Graph Builder might be valuable, but in case you want to get also statistical analysis involved you should look for other analysis like Fit Y by X (ANOVA, Bivariate, ...), or Distribution. Especially in case you want to understand what's driving your response to increase GB is a good tool to start, looking further into Distribution, Fit Y by X as well other kind of one or two factor at a time approaches. Ending up with a Fit Model taking into account also other effects than just the main effects. With the profiler you then can optimize, simulate and play around for different factor settings to find other conclusions.Too make it more concrete here two screenshots. Left with PH as nominal (can see the box), right as continuous(just a line):
Best, Martin
You could try to "bin" your pH values so that you have fewer boxes in the box plot, but still use a continuous x for the display. Create a new column with the following formula (assuming your x axis is in the column "pH"). Change the number to define your number of "bins" (in the case: 20), which will change the number of box plots and, in effect, their width..
Col Minimum( :pH ) + Round(
(:pH - Col Minimum( :pH )) / ((Col Maximum( :pH ) - Col Minimum( :pH )) / 20),
0
) * ((Col Maximum( :pH ) - Col Minimum( :pH )) / 20)
For the quantitative analysis, use the proper pH, instead of the binned pH. Binning is just for displaying.
Plot of pH vs binned pH, with 20 bins and 50 bins.
