Double_t MyFitFunction(Double_t* x, Double_t* parameter) {

	Double_t funtionValue;
	
	if (x[0] <= 24.77) {
		functionValue = parameter[0] + 
							 parameter[1] * x[0] ;
	} else {
		functionValue = parameter[2] + 
										parameter[3] * x[0] +  
										parameter[4] * x[0] * x[0] +  
										parameter[5] * x[0] * x[0] * x[0] + 
										parameter[6] * x[0] * x[0] * x[0] * x[0];
	}
	
	return functionValue;
}