Paired sampling

For the statistical analysis, the Hllcoxon Paired-Sample Test was used. A test for a one-tailed hypothesis with paired samples was used In the procedure for nonparametrlc data since It could not be assumed that the levels of residue detected were from a normal distribution and It was expected that the residues would decrease with time. 

The most frequently used tests in quality control in the flavour industry are paired-sample comparison tests, and triangle tests, which are often combined with the description of deviation from a reference item. For the selection and training of panellists, further test methods are used, for example ranking tests for colour, taste and odour, threshold detections (taste, off-flavour), colour blindness tests and odour identification tests [6]. 

Figures 3 and 4 display the paired results obtained with Ab-cor and 3M diffusion-type samplers, respectively. These results were analyzed through use of the "t" test for paired samples and the calculation of correlation coefficients and regression equations, with the results of these analyses shown in Table I. A statistically significant correlation is seen between the data set for each type of diffusion sampler and the corresponding tube/ pump sample data set, and the "t" test fails to refute the null hypothesis that there is no significant systematic difference between each of the diffusion sampler data set and the corresponding tube/pump data set.

Calculate t for paired samples. With d as the average difference (algebraic), Sd the standard deviation of the differences, and n the number of pairs ... 

All data were analyzed as paired samples using the Wilcoxon test. For all calculations, SPSS software was used. 

The intensities of umami of these two samples were compared in various amino acid solutions using a paired sample test. In each pair, the panelists were asked to indicate which umami is stronger. No significant difference was recognized except for... 

Differential in-gel electrophoresis (DIGE) facilitates protein expression by labeling different populations of proteins with fluorescent dyes. Typically, paired samples from the normal and tumor region are labeled with Cy3 and Cy5. After analysis by differential analysis image software, protein spots that exhibit a significant difference in intensity are excised for in-gel tryptic digestion and MS analysis. 

Describe four widely applicable non-parametric methods (Mann-Whitney, Wilcoxon paired samples, Krukal-Wallisand Spearman correlation)... 

Wilcoxon paired samples test - a substitute for the paired f-test... 

In the paired t-test we calculate the change in a measured end-point for each individual and the test expects these differences to form a normal distribution. If this condition is not met, the Wilcoxon paired samples test can be used instead. 

Figure 17.5 strongly suggests that this treatment is much more likely to lead to an increase than to a decrease in haemoglobin levels, but a formal test is required. No transformation is going to convert this to a normal distribution. With normally distributed changes, we would have used a paired f-test, but with this data we will change to the Wilcoxon paired sample test. 

Non-parametric Mann-Whitney test Wilcoxon paired samples test Kruskal-Wallis test Spearman correlation... 

Wilcoxon paired samples test equivalent to the paired /-test ... 

The paired samples which were collected at each site were compared to the results of the 10 sampler experiment to detect samples of poor quality. This procedure was utilized to insure than experimental uncertainties did not contribute to the observed variation in composition. The variance for each species listed in Table 1 from the control site was statistically compared to the variance for the paired samples at all sites with an F-test. One of the paired measurements at a site was rejected if their variance was significantly (p <0.005) greater than measured at the control site and one of the pair had a significantly (p <0.005) poorer charge balance (sum of... 

If the volume values from treatment and control probes come, for example, from the same patient or, as in DICE experiments, from the same gel, then there is a dependency between the resulting values. Hence, the t-test for paired samples, which has even a higher statistical power than the t-test for independent samples, can be used here. The term power is explained below. For the paired t-test the difference d between the treatment and control value is used. 

For each single spot the t-test for paired samples tests the null hypothesis Hq, that there is no expression change for this spot, versus the alternative hypothesis, Hj that there is an expression change. Based on the sample, the test decides either to accept Hq or to reject it and accept Hj. 

This t test for related samples can be used to compare a new analytical method and the reference method (Massart et al. 1990), to compare the amino acid content between different stages of the elaboration processes for wines from the same batches (Marcobal et al. 2006b), and more generally, to compare paired samples. 

Bischoff A., Palme H., Schultz L., Weber D., Weber H., and Spettel B. (1993b) Acfer 182 and paired samples, an iron-rich carbonaceous chondrite similarities with ALH85085 and relationship to CR chondrites. Geochim. Cosmochim. Acta SI, 2631-2648. 

A comparison of means of paired samples is used when an external factor influences the data sets in a way that is point-by-point identical ... 

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