In order to get a closer look at what is happening in different economic levels, the different countries are stratified according to their income levels. With this in mind, the results for low-income countries that have a GNI per capita of less than or equal to 1,035 US$. It is notable that there are no significant correlations between the four pairs.
Table 4. Correlations for parameters (low-income countries).
      Spearman’s rho p
GDP - Incidence Rate -.167 .434
GDP - Mortality Rate .051 .812
GDP per Capita - Incidence Rate .143 .505
GDP per Capita - Mortality Rate .070 .743
* p < .05, ** p < .01, *** p < .001
            The results from low-middle income countries, countries that have a GNI per capita between 1,036 US$ - 4,045 US$, are shown in the table below. The correlation between the GDP and the incidence and mortality rates of the low-middle income countries are not significant. However, the correlation between the GDP per capita of the incidence (rs = .362, p < .011) and mortality rates (rs = .348, p = .014) are statistically significant, with the correlation being weak.
Table 5. Correlations for parameters (low-middle income countries).
      Spearman’s rho p
GDP - Incidence Rate .019 .896
GDP - Mortality Rate .127 .385
GDP per Capita - Incidence Rate .362* .011
GDP per Capita - Mortality Rate .348* .014
* p < .05, ** p < .01, *** p < .001
            For the upper-middle income countries, the results of the statistical analysis are shown below. Upper middle-income countries have a GNI per capita between 4,046 US$ and 12,535 US$. As with the case for low-income countries, there is no significant correlation between the four factors mentioned below.
Table 6. Correlations for parameters (upper-middle income countries).
      Spearman’s rho p
GDP - Incidence Rate .107 .457
GDP - Mortality Rate .272 .056
GDP per Capita - Incidence Rate .112 .437
GDP per Capita - Mortality Rate -.001 .993
* p < .05, ** p < .01, *** p < .001
            High-income countries are countries that have a GNI per capita greater than 12,535 US$. With this in mind, the results for these countries are shown below. As with the case for the low-income and upper-middle income countries, the correlations are not statistically significant.