How to save user input as variable I can compare?

I am trying to generate by Linear regression to get value a, then I want to get user input value b. So I can then take value a and b and plot them on a curve. But my user input is not storing values?   % Linear regression model: y ~ 1 + x1, calculate R^2 values for each ingredient Mdl1=LinearModel.fit(SortedData_Cement(:,1),SortedData_Cement(:,9)); R^2_Cement = Mdl1.Rsquared.Ordinary; Mdl1=LinearModel.fit(SortedData_Blastfurn(:,2),SortedData_Blastfurn(:,9)); R^2_Blastfurn = Mdl1.Rsquared.Ordinary;   % Prompt user to input a value for R^2 for all ingredients, accepting or rejecting value within a range. Display message to user. exit=false; msg='Please enter an R^2 value for Cement:'; while ~exit data = str2double( inputdlg(msg) ); exit = (0<= data && 1>=data); if ~exit msg = 'Input must be between the values 0-1. Please re-enter: '; end end   exit=false; msg='Please enter an R^2 value for Blast Furnace:'; while ~exit data = str2double( inputdlg(msg) ); exit = (0<= data && 1>=data); if ~exit msg = 'Input must be between the values 0-1. Please re-enter: '; end end