Fig. 4
a Correlation coefficients between co-location degree centrality and estimated basic reproduction number and the p-values for 20 counties with the greatest number of confirmed cases on March 31; b distribution of correlation coefficients for all counties; and c distribution of p-values (orange) for the correlation analysis for all counties. The data for confirmed cases is based on the CDC reports on March 31, 2020 (red). The error bar represents the two-side 95% confidence interval. Some extreme numbers of confirmed cases are considered as outliers and are not included