log - - - - figure the chlorine concentration seems to have an exponential decay recall that for general regression problem the learner gt (xfor given training set is obtained by minimizing the training (squared-errorloss ` ( ( ) (yi (xi )) = ( the third strategy for regression with nonlinear prediction functions is to directly minimize ( by any means possibleas illustrated in the next example example (hougen functionin [ the reaction rate of certain chemical reaction is posited to depend on three input variablesquantities of hydrogen -pentane and isopentane the functional relationship is given by the hougen functionyb / where are the unknown parameters the objective is to estimate the model parameters {bi from the dataas given in table table data for the hougen function the estimation is carried out via the least-squares method the objective function to minimize is thus ! xi xi / ` ( ( )yi ( = xi xi xi