The results were overall similar whether or not age was controlled for, with only slight decreases in the size of the correlation for the partial correlations.
Furthermore, cluster will be used as a random effect to control for intracluster correlation and subject will also be used as a random effect to control for the correlation of multiple events for the same individual.
For the assessment of correlations, Spearman correlation coefficients were calculated.
There was no correlation for the control without earthworms.
Correlations were evaluated by the calculation of Pearson's r-coefficient; the significance of the correlations were also controlled for the confounding factors BMI and smoking.
When separated, the correlations were significant for the altitude and control groups, with the correlation being stronger for the altitude group (slope of 0.57 to 0.72).
Within each of the case and the control groups, correlation for CRY2 and GAPDH expression levels to age was tested and showed no significant correlation.
After controlling for age, the correlation between the maximum level of performance during the experiment and the children's total IQ score was 0.594 (p < .001, partial correlation).
Likewise, computing partial correlations between age and each of the acuity measures, while controlling for cognitive processing, resulted in little attenuation of the correlations provided in Table 7.
After controlling for the sizes of the invasive component, the partial correlation coefficient was still significant at 0.08 (P=0.01).
However, the rank order correlation of dN/dS ratios for individual candidate genes was very low, less than the correlation for the control genes.
