Null effects are open to a number of interpretations, particularly the possibility of a Type 2 error (i.e., failing to find a true difference due to lack of power or other methodological error).
Thus, we adopt the criterion that the difference between the two methods should be greater than 1 kb (dashed line Figure 3b) for it to be regarded as a true difference due to the method used.
Although it is tempting to localise a cluster to a single tract for these reasons, this assumes that any true difference corresponds to the morphology of a tract, and that the cluster is only a partial capture of that true difference.
That is, we may have missed a true difference due to poor statistical power.
An I value represents the percentage of total variation across studies due to true difference rather than to chance, with values of 0%to30%0%, 31% to 50%, and >50% representing mild, moderate and notable heterogeneity, respectively [ 14].
It is possible that intraindividual variability between replicate measures could be greater than the interindividual variability across samples, which would make it difficult to decipher true differences due to exposure versus differences that occur naturally in the population.
Post hoc power calculations were performed, using the effect sizes derived from this study to determine if the study sample had sufficient power to enable a true difference in estimates to be detected if they truly existed [ 23, 24].
The gender differences in prevalence of wheeze and asthma attack did not reach statistical significance because the true differences appear to be quite small to be significantly detected based on our sample sizes of males and females.
Sometimes people think to make a true difference you have to give a lot of money and then giving back gets overwhelming or unachievable for them.
It is difficult to say whether this is a true difference or due to a responder bias, both for adults and for the children's parents/caretakers.
