> in any case, the observed results should be verified in future by using some more representative data, for instance collected by an internet questionnaire, or by repeating the study on other samples that would not be self-selected for better health or altruism > another problem of the present study is the relatively low number of male participants, which may have led to false negative results for some analyses on this subset. most associations observed in men were non-significant and the size of all effects was lower than in women. on the other hand, the size of many formally non-significant effects was relatively high, and one path analysis model for men revealed a significant positive effect of redheadedness on sexual desire. the absence of evidence of the effects of redheadedness in men therefore should not be interpreted as a non-existence of those effects > it is fair to mention some limitations of the statistical methods used in this study. as mentioned above, the absence of statistical evidence for the existence of an effect is not a proof of its non-existence. specifically, the path analysis did not find any evidence of a mediating role of increased sexual desire in the effect of redheadedness on sexual activity. in fact, the strength of the indirect (mediated) effect of redheadedness on sexual activity was much lower than the strength of the direct one. however, the observed differences in the strengths of direct and indirect effects could be caused not only by a real difference in effect strengths but also by differences in the precision of measurement of variables in the model. if, for example, women were willing to truthfully report the frequency of their sexual activity but reluctant to truthfully report the intensity of their sexual desire, then any statistical method, including path analysis, would necessarily underestimate the power of any mediating effect of sexual desire
Brazil