The rule states that altruism can evolve in a population if the fitness cost to the donor is less than the fitness benefit to the recipient, discounted by a "coefficient of relatedness" between the two (1/2 for parent-offspring or between full siblings, 1/4 for nephews and nieces, 1/8 for first cousins, and so on).
Two-component isotropic mixtures may be characterized by a correlation coefficient between sample compositions.
This assumption is supported by a coefficient of correlation of 0.83 between daily PM2.5 absorbance and NO2 levels measured at one monitoring station in Erfurt, Germany, from 2001 to 2002 (Cyrys J, personal communication).
Heteroscedasticity can be revealed by calculating a correlation coefficient between the absolute difference and the average of the test sessions.
Variations caused by threshold/cut off effect are detected by a Spearman correlation coefficient between the logit of sensitivity and logit of 1-specificity with a significant p-value [ 27, 32, 33].
Indeed, considering at first a SISO case, if we denote by the channel coefficient between a single transmit antenna and the receive antenna at subcarrier, the despreaded signal is given by (50).
To compensate for the phenomenon of heteroskedasticity (i.e; the variance increases with the mean) – documented by a 0.89 correlation coefficient between the subject-specific between session standard deviation and mean – we log-transformed FE NO values, yielding the log FE NO.
The judgement accuracy is represented by the correlation coefficient between a participant's judgements (e.g. "at risk") and ecological criteria ("presence of a critical event").
I is the correlation between P and C while controlling for I, defined by where r PI is a correlation coefficient between variable P and I, r PC is a correlation coefficient between variable P and C and r CI is a correlation coefficient between variable C and I.
According to the guidelines by Cohen et al. [ 37], a correlation coefficient between 0.10 and 0.29 corresponds to a small strength of correlation, 0.30 to 0.40 denotes a medium correlation and 0.50 to 1.0 signifies a high correlation between the variables.
