The phrase "a reference ratio" is correct and usable in written English.
It can be used in contexts where you are discussing a specific ratio that serves as a standard or benchmark for comparison.
Example: "In our analysis, we will use a reference ratio to evaluate the performance of the investment portfolio."
Alternatives: "a benchmark ratio" or "a standard ratio".
In gene expression studies, qPCR data need to be normalized to remove nonspecific variability associated with differences in RNA quantity and quality, usually by relative quantification whereby the expression level of the target gene is determined relatively to another gene transcript, the so-called reference gene (RG), and the results are expressed as a target to reference ratio [ 6].
Each gpr- and jpg-file was then further processed in the J-Express (version 2.7) software package [ 55] and organized into a gene expression matrix where each row represents a clone, each column represents a sample (salmon louse) and each cell contains a log2 (sample vs. reference) ratio.
For clustering, clones were chosen based on the entire tumor sample set; they were accepted if they were present in at least 80% of cases and showed a log2 test over reference ratio [log2 (t/r)] of less than -2 or greater than 2 in at least one case, resulting in a total of ~4,000 genes.
A rigorous application of the reference ratio method would require the construction of a proper joint probability distribution over pairwise distances.
In the next section, we show that the standard pairwise distance PMFs can be seen as an approximation of the reference ratio method.
Therefore, the application of the reference ratio method results in a useful approximation, at best.
Fourteen (50.0%) patients had a CD4 CD8 ratio less than the standard reference ratio of 1.4.
The data were normalized to corresponding naïve control, a reference group, (Ratio = (eff target gene)ΔCTtarget (control-treated)/ eff reference gene)ΔCTreference (control-treated)).
This method is based upon the quantitative analysis of the non-clay minerals using a reference intensity ratio method, combined with measurement of the 020 reflection for phyllosilicate minerals which is assumed to correspond to the amount of clay mineral present [93].
Our computations indicate that the power to detect rare CNVs is maximized for a reference:test ratio of ∼10 1.
