Linear fit between two sets of independent variables

조회 수: 4 (최근 30일)
AKHILESH KUMAR
AKHILESH KUMAR 2016년 12월 9일
편집: Star Strider 2016년 12월 9일
i have data set like
X Y
1 1.005388889
2 0.624308036
5 0.622771858
7 0.294506747
9 0.187576608
i want to plot linear fit showing equation and R-square value on the graph, as shown in figure plotted by excel.

답변 (2개)

Jos (10584)
Jos (10584) 2016년 12월 9일
Here are some commands you may find useful. Please take a look at the documentation
X = [...]
Y = [...]
plot(X, Y, 'bo')
[r,p] = corrcoef(X, Y)
p = polyfit(X, Y, 1)
lsline

Star Strider
Star Strider 2016년 12월 9일
편집: Star Strider 2016년 12월 9일
It is not as straightforward as it at first seems.
The Code
% X Y
D = [1 1.005388889
2 0.624308036
5 0.622771858
7 0.294506747
9 0.187576608]
X = [D(:,1) ones(size(D(:,1)))]; % Design Matrix
B = X\D(:,2); % Estimate Parameters
Yfit = X*B; % Calcualte Regression Line
Resid = D(:,2) - X*B; % Residuals
Rsq = 1 - sum(Resid.^2)/sum((D(:,2)-mean(D(:,2))).^2); % Calcualte R^2
figure(1)
plot(D(:,1), D(:,2), 'bd', 'MarkerFaceColor','b')
hold on
plot(D(:,1), Yfit)
hold off
axis([0 10 0 1.2])
lbl = sprintf('y = %.3f\\cdotx%+.3f\nR^2 = %.3f', [B' Rsq])
text(6, 0.8,lbl, 'HorizontalAlignment','center')
The Plot
EDIT Typographical error in the ‘lbl’ string. Corrected now.

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