If someone were interested in the link between inequality and inflation a scatter plot would be a perfectly reasonable place to start.
The issue is that the scatter plot shows there are something like 30 countries with an inflation rate of 0-15% and no correlation between inflation+gini/inflation+growth and then 8 countries where there is.
This is an interesting question, but that's [1] a terrible study.
It compares "data averaged over 5-year periods" across different countries. It's effectively a scatter plot of income inequality versus inflation.
The study's findings are better stated as "countries with high inflation have worse income distributions." Which makes sense. High-inflation countries tend to have low-quality institutions and low economic growth, factors which make being middle class difficult and poor miserable.
The right way to do this is longitudinally, studying populations over time. Even that's hard, given the number of interceding factors. At a minimum, an input must be the distribution of credit and debt, given inflation transfers wealth from the former to the latter.
[1] http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.295...