MATLAB: Create confidence interval for linear regression line

MATLAB and Simulink Student Suiteregression

Hi, how can I plot a confidence interval bound for the regresison line using lsline? The code I wrote is this:

clc, clear all, close all
X(:,1) = (1:1:100);
X(:,2) = rand(100,1);
figure;
hold on
plot(X(:,1),X(:,2),'b*','MarkerSize',5);
h = lsline;
set(h,'color','g','LineWidth',3)
%s = lsline + 0.95 * h;
title 'TRY';
xlabel 'X'; 
ylabel 'Y'; 
hold off

Thank you

Best Answer

I would use the fitlm (link) function to calculate the regression line, the the predict function to calculate the confidence intervals. If you want to use polyfit and polyval instead, you can use the File Exchange contribution polypredci.

Related Solutions

MATLAB: Estimate confidence intervals after regress!

The ‘BINT’ matrix contains the parameter confidence intervals.

If you want both parameter and prediction confidence intervals, use fitlm:

x = (1:10)';                                        % Create Data

y = 1.5 + 2.3*x + 1.5*randn(size(x));               % Create Data
mdl = fitlm(x, y);                                  % Fit Data
B = mdl.Coefficients.Estimate;                      % Coefficients
CI = coefCI(mdl);                                   % Coefficient Confidence Intervals
[Ypred,YCI] = predict(mdl, x);                      % Fitted Regression Line & Confidence Intervals
figure(1)
plot(x, y, 'pg')
hold on
plot(x, Ypred,'-r',    x, YCI, '--r')
hold off
grid

MATLAB: Binary Logistic Regression Curve

Use the fitglm function to fit logistic regression model to data. Check the following code for example,

% Create random data
x = rand(100, 1);
y = x > 0.5;
y(1:50) = x(1:50) > 0.3; % To avoid perfect seperation
% Fit model
mdl = fitglm(x, y, "Distribution", "binomial");
xnew = linspace(0,1,1000)'; % test data
ynew = predict(mdl, xnew);
scatter(x, y);
hold on;
plot(xnew, ynew);

This will give following output.

Best Answer

Related Solutions

MATLAB: Estimate confidence intervals after regress!

MATLAB: Binary Logistic Regression Curve

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