www.gusucode.com > stats 源码程序 matlab案例代码 > stats/FitLinearRegressionUsingSpecifiedModelFormulaExample.m
%% Fit Linear Regression Using Specified Model Formula % Fit a linear regression model using a model formula specified by % Wilkinson notation. %% % Load the sample data. load carsmall %% % Store the variables in a table. tbl = table(Weight,Acceleration,Model_Year,MPG,'VariableNames',{'Weight','Acceleration','Model_Year','MPG'}); %% % Fit a linear regression model for miles per gallon (MPG) with weight and % acceleration as the predictor variables. lm = fitlm(tbl,'MPG~Weight+Acceleration') %% % The $p$-value of 0.18493 indicates that |Acceleration| does not have a % significant impact on |MPG|. %% % Remove |Acceleration| from the model, and try improving the model by adding % the predictor variable |Model_Year|. First define |Model_Year| as a nominal % variable. tbl.Model_Year = categorical(tbl.Model_Year); lm = fitlm(tbl,'MPG~Weight+Model_Year') %% % Specifying |modelspec| using Wilkinson notation enables you to update % the model without having to change the design matrix. |fitlm| uses only % the variables that are specified in the formula. It also creates the necessary % two dummy indicator variables for the categorical variable |Model_Year|.