With this information at hand, we have in retrospect calculated that the study had 80% power to detect group differences between preterm and control subjects of approximately 5.5 points, providing that the level of significance was set at 0.05.
In this study, the nanoparticles were subjected to a magnetizing field of approximately 40 gauss for 0.75 seconds followed by a delay of 35 milliseconds and subsequent detection every millisecond of the relaxing magnetic field for 2.2 seconds by using a seven-channel SQUID sensor array (BTi 2004; 4D-Neuroimaging, San Diego, CA, USA), which has been described in detail elsewhere [ 6].
It is then possible to demonstrate, within 80 125% confidence limits and a subject population of approximately 20, that two formulations are bioequivalent.
First, this was only a modest size cross-sectional study of approximately 350 subjects and the result needs further confirmation in other cohorts.
For example, in one study of approximately 1,000 subjects 50 70 years of age with mainly environmental lead exposure, the mean blood lead level was approximately 4 μg/dL and the mean tibia lead level was approximately 19 μg/g, but the Pearson's r correlation between the two was only 0.12 at a time of low ongoing environmental lead exposure (Martin et al. 2006; Schafer et al. 2005).
Although no test-retest study was performed, average inter-subject variability of approximately 15% was observed, which implies a good reproducibility.
Transcriptional profiles of RNA Later and frozen samples showed a within-subject correlation of approximately 0.93.
For each subject, an average of approximately 85.1% of the reads could be mapped to the human reference genome.
Apparently, even in the optimal situation with respect to the degree of sequence divergence, the tree edge length measurements for a single gene are subject to variation of approximately 0.45 natural log units (table 1; Wolf et al. 2013).
