INDEX Regression curve

Plot net RFI versus protein concentration (%), and then find the slope (S0, a hydrophobic index) of the line by linear regression analysis (or the initial slope at the origin of quadratic fitting for a more precise measurement as seen in Figure B5.2.1, curve 1). 

In Fig. 18.3 the parameter p is plotted versus Tg, as an index of the molecular stiffness of the polymer. The data show a considerable scattering, but the general course is unmistakable (Van Krevelen, 1972). The drawn curve corresponds to the following equation, as obtained by linear regression (correlation coefficient is only 0.86) of all data ... 

For this study, we selected 42 representative FGs from a list of more than 500 substituents compiled by Hansch et a/.128 The electrophilicity index co for the whole series of ethylene derivatives, together with the experimental electronic substituent effects from the reactivity index co was as follows we first compared the computed co values with the experimental crp (see Figure 8). The analysis revealed a poor linear correlation between both quantities, with a regression coefficient R2 = 0.53. A better correlation was found when all the 42 points were fitted to a logarithm curve (.R2 = 0.84, see Figure 8). 

The use of this relation to evaluate experimental data is essentially curve htting since it has no mechanistic base. Values of K provide an index of the extent of sorption and often are listed without units. However, if sorption (x/m) is expressed as pmol/g and equilibrium concentration (Ce) in pmol/mL, K would have units (pmol) " mL" g The exponent, n, simply indicates whether the relation between xlm and Ce is linear (n = 1), concave down (n < 1) or concave up (n > 1), Figure 3.4. Values for the Freundlich K and exponent n derived by a simple regression from the experimental data summarized in Table 3.2 are given in Table 3.3. 

Refractive index as a function of wavelength for the H - and Li -implanted and annealed Regression fitting curve along with the curve for as-deposited films are also given for reference. 

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