values > 1 in Oneway Analysis: Compare Densities: what are they?

[#1]

In the simple Oneway analysis platform, there is an option to compare what I understood to be probability densities from x conditions, along with the CDF.   However, the y-axis scale is ... confusing, in that it goes above 1 (as shown in fig).   And in fact can go up past 2.5. 

Anyone know what this number actually represents? I couldn't find it anywhere in the documentation. 

Thanks in advance!

[#2]

Compare Densities

Shows or hides a plot of overlaid probability density functions for each group.

https://www.jmp.com/en/statistics-knowledge-portal/inferential-statistics/probability-distributions , The range of the PDF is non-negative and the integral over all values of the random variable is one.

[#3]

thanks - yours truly was confusing probability density and probability mass....