DNA samples from HeLa, Jurkat and Daudi cell lines were used as positive controls in every experiment and to standardize interassay variation [ 21].
Data were collected by many observers and, although attempts were made to standardize procedures, variation in recording is likely to have occurred.
After we standardized the variation attributable to each factor, we calculated the proportion of total variance each factor explained.
According to the least-action principle in gait, when the plantar stance area of one stride cycle is standardized, the variation of the plantar stance area of both types of foot can be obtained.
Quantitative reporter assays were done in co-transfection experiments in order to standardize experimental variations like transfection efficiency or differences in cell numbers between samples.
Primers specific for human β-actin cDNA were added to a parallel reaction to standardize for variations in PCR between samples.
In order to standardize the variations, the stone non-cholesterol sterols were expressed as milligrams by stone weight and in terms of 10 × mmol of non-cholesterol sterol /mol of cholesterol (called proportions or ratios in the text).
This standardized geographic variations across carriers.
Further, artificial multiplicative effects are introduced during data preprocessing, for example, if expression values are standardized, then variations stemming from noise scale the signal.
To standardize for interlaboratory variation, all subjects were classified as low (1 33 percentile), medium (34 66 percentile), or high (67 100 percentile) according to tertiles of CA frequency distribution.
To standardize for interlaboratory variation, all subjects were classified within each laboratory according to tertiles of CA frequency as follows: low (1 33 percentile), medium (34 66 percentile) or high (67 100 percentile).
