Students t-test

The standard deviation of the distribution of means equals cr/N. Since cr is not usually known, its approximation for a finite number of measurements is overcome by the Student t test. It is a measure of error between p and x. The Student t takes into account both the possible variation of the value of x from p on the basis of the expected variance and the reliability of using 5- in... 

All results were evaluated using the Student t-test, at the 5 % level of statistical significance. 

The data to be examined are correlated with eq. (24). Successful correlation with eq. (24) is a necessary but not sufficient condition for the existence of case (a). Strong evidence for case (a) is provided by a confidence level of Ij greater than or equal to 90.0. The confidence level of p is obtained by means of a student t test of. If is not significant, then this fact implies either the existence of cases (b), (c), or (d), or the use of an incorrect steric parameter. The data are now correlated with eq. (2). If the correlations with... 

Figure 5. Histogram Th/U for clinopyroxenes in peridotites and pyroxenites from the Ronda peridotite massif Concentrations were measured by isotope dilution mass spectrometry in acid-leached clinopyroxenes. This histogram shows that pyroxenites do not have larger Th/U ratios than peridotites. Thus, the correlation found between ( °Th/ U) and Th/U cannot be explained by mixing of peridotite and pyroxenite melts as advocated in Sigmarsson et al. (1998). Data from Hauri et al. (1994) and Bourdon and Zindler (unpublished). It can be shown with a simple Student t-test that the two populations are indistinguishable.

Tensile testing is susceptible to invalid runs due to sample flaws, poor mounting, or many other other sources of error. It is therefore essential that outliers be identified and removed. After all runs have been analyzed, STRESS calculates means and standard deviations for each parameter. It also performs Student t-tests on... 

Statistical analysis Statistical analysis consists of determination of Standard error of means (SEM) or the Student- t-testing. The measurement error was about 1-2% (10 spectra per one variant, n=10). Counting was performed in four or five replicates (the number of Petri dishes per a treatment). SEM for the fluorescence spectra was 2 %. 

Figure 2.3 shows the results obtained in a comparision of these methods on a range of deep-sea and offshore samples. The line of gradient 1.0 on each diagram shows the result which would have occurred had agreement been obtained. The Student t-test showed that in both exercises the colorimetric method with iodine water treatment yielded higher values than that without... 

Statistical Methods. Means of treatment groups for plasma retention of BSP, plasma osmolality, total plasma protein concentration and urine flow rates were compared by students t test for independent sample means (17). Plasma enzyme activity data were converted to a quantal form and analyzed by the Fischer Exact Probability Test (18). Values greater than 2 standard deviations (P < 0.05) from the control value were chosen to indicate a positive response in treated fish. 

Shankland, K., Gilmore, C.J., Bricogne G. and Hashizmne, H. (1993) A multisolution method of phase determination by combined maximisation of entropy and likelihood. V Automatic Likelihood analysis via the student t-test, with an application to the powder structure of magnesium boron nitride, Mg3BNs. Acta Crystallogr. A49, 493-501. 

Figure 6. Semi quantitative evaluation of spontaneous adsorption of collagen IV conjugated with a fluorescence marker Oregon Green 488 (A) to polyethylene foils iradiated with ions (energy 30 keV, dose from lO to lO ions/cm ), and its correlation with the number of rat aortic smooth muscle cells initially adhering to the polymer on day 1 after seeding (B). Collagen was diluted in phosphate-buffered saline to the concentration of 0.02 mg/ml (10 pg/cm ) and incubated with the foils for 24 h at room temperature. Mean+SEM from 4-9 experiments. Student t-test for unpaired data [43].

Figure 8. Concentration of markers of adhesion (A) and differentiation (B) in rat aortic smooth muscle cells in cultures on polyethylene (PE) modified by irradiation with ions (energy 30 keV, doses from lO to lO ions/cm ). Measured by enzymatic immunosorbent assay (ELISA) per mg of protein, absorbances expressed in % of the values obtained on pristine non-modified PE. Mean + SEM from 4 experiments. Student t-test for unpaired data, p<0.05 p<0.01 compared to the values on pristine PE.

FIGURE 4.3 Antihypertensive activities of ACE-inhibitory peptides after single oral administration in SHRs. SHRs were administered captopril (O), the ACE-inhibitory peptide from rotifer ( ) at a dose of 50mg/kg. Changes in systolic blood pressure were expressed as mean SE [n—5). Statistical analyses were done by Student t-test (P<0.05) (Skeggs et at., 1957). 

Gangliosides assayed were eluted from the plate shown in Figure 3, diluted, and the amount derived from 0.1 g of brain was added to the PFC assay cultures. Values are the mean standard error of five cultures. Application of the Student t test to the standard errors for the samples gave p values less than 0.05 when compared with the Thy-l-active fraction. Positive control for the anti-Thy-1.2 PFC assay was a column GM1 fraction containing Thy-l glycolipid (15). 

Factors X4 and X7 with their respective effects EXi=13.0, EX4=14.5 and EX7=19.5 are also screened out visually from the scatter diagram. A statistical significance check of these effects is done by quantitative calculation of their values through a table with three inputs and a check with the Students t-test. An auxiliary table with three inputs is shown in Table 2.41. 

The replication error in measuring the catalyst activity is Syi=3.24, and durability Sy2 =2.37. The adequacy of the regression equations (3.81) and (3.82) is tested using the Student t-test at the control-test points 8, 9 and 10, Table 3.28. 

Statistical analysis for these assays can be performed using many statistical programs including a twotailed student t-test or a KruskalWallis nonparametric analysis of variance on averaged triplicate values. 

In all the tables of estimated coefficients in this section the values in brackets represent the standard errors of the coefficient estimates and indicates the coefficient estimates were at least significant at the 95% level using a student t test. 

Finally, all effects were evaluated by "Student t-test" and "F-test" methods, in order to check whether these effects were simply due to experimental error rather than being statistically significant. Decisions are based on a certainty of at least 95%. Significant... 

Mean values of the dosage groups are compared to the controls. Statistical significance is evaluated by means of the Student t-test. 

Statistical parameters, when available, indicating the significance of each of the descriptor s contribution to the final regression equation are listed under its corresponding term in the equation. These include the standard errors written as values, the Student t test values, and the VIF. The significance of the equation will be indicated by the sample size, n the variance explained, r the standard error of the estimate, s the Fisher index, F and the cross-validated correlation coefficient, q. When known, outliers will be mentioned. The equations are followed by a discussion of the physical significance of the descriptor terms. 

The significant differences in Np and in PSD, in terms of S.D., were confirmed by the Student t-Test and the F-test, using the procedures described by Li (27). 

FIGURE 45.3. The effects of DFP on the HSP 27 and HSP 70 levels in myoblast, myoblasts in fusion, and myotube cultures. Levels of HSP 27 and 70 were determined 24 h after addition of DFP at the 10 M concentration. They were quantitated by Western blot with Chemi Genius Biolmaging System (Syngen, Cambridge, UK). Significant difference (Student t-test, p < 0.05 n — 4) between control and DFP-treated cultures was observed in all determinations except for HSP 70 in myoblasts. 

FIGURE 45.4. The effect of acute h poxia on HIF-1 a expression in human myoblasts. Human myoblasts were exposed to 1% O2 for 4 h. A representative Western blot is shown on the left. Relative expression level of HIF-1 a (three independent experiments) is shown on the right (arbitrary units, control = 1) (Student t-test, p = 0.004). Quantification was performed with Chemi Genius Bio-Imaging System (Syngen, Cambridge, UK). 

---