Selecting the order in a family of homologous models

In Example 3.5.1 we used ridge regression to confirm that the simpler model 

Suppose the vapor pressure is exact to three digits and give an estimate s2 for the logarithms. Apply (3.104) replacing o2 with s2. 

4 Error—in-variables estimation of van Laar parameters from vapor—liquid equilibrium data 

At low pressures the following equations are valid for a binary vapor—liquid mixture  

Pj°(T) equilibrium vapor pressure of pure component i activity coefficient of component i. 

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