Quantitative evaluations of gages being in same geographic cluster region for 50-70 and 75-95 groupings

[jds485]

Similarity could result from extreme events (>75th percentile) that are within both the 50-70 and 75-95 groupings, so it will be important to redefine events within #137 before making conclusions from this assessment.

Goal is to compare for each gage if it’s in the same geographic cluster region for each quantile grouping (50-70 and 75-95), considering error in the seasonal flow metric values for each region (barplots with error bars). This will be a more convincing way to make statements about similarity of the 50-70 and 75-95 cluster regions as compared to visual map comparison.