We computed the relevant summary measures for Mexican American, non-Hispanic black, and non-Hispanic white race/ethnicity categories available in NHANES, but not the other Hispanic or "other race" categories because their small sample sizes do not permit generating reliable estimates [ 16] and because of potential heterogeneity of exposure patterns in these subpopulations [ 17].
We did not attempt to capture the genetic variation of African populations because our sample size did not have sufficient power to conduct African American-specific analyses.
The maximum life span was not analyzed because the sample size did not support a rigorous statistical analysis of this trait.
However, these findings may be of limited value because small sample size did not allow us to examine this relationship accurately.
In most established association and GWA studies published so far, BP values reported are biased by the antihypertensive treatment ignoring the therapy or solving by adding 10 15 mmHg to the observed BP values, because the need of very large sample sizes doesn't always allow detailed enrolment [19], [20], [43].
The strong trend showing increases in parent report of child tooth brushing frequency did not reach significance, perhaps because the reduced sample size did not have sufficient statistical power to detect difference or because dichotomisation of responses reduced the sensitivity of the measure.
We hypothesise that this is either because the small sample size did not allow reliable quantitative measurements, the NOC personnel misapprehended the relative hierarchicality of the NOC and ORH, or there are problems with the validity of the CVF instrument.
Because our small sample size did not permit equal distribution of potential confounders, we also performed multivariate analyses, using linear regression and logistic regression, to account for baseline differences in the intervention and control groups.
Second, and most importantly, because our limited sample size does not allow pinpointing with complete certainty which species have exchanged genes and which have not.
It is recognized that the statistical significance of a treatment effect, because of its partial dependency on sample size, does not always correspond to the clinical relevance of the effect.
