If I have three graphs and I want to place them over one another so that their mean values align, and then want to create a trend line among those graphs how would I do this?

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Keon Walters 2018-7-13

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https://ww2.mathworks.cn/matlabcentral/answers/410298-if-i-have-three-graphs-and-i-want-to-place-them-over-one-another-so-that-their-mean-values-align-an

评论： Keon Walters 2018-7-16

%example
x=[1:0.03:500];
y=x^4;
i=[100:0.01:600];
y2=x^2+30;
plot(x,y,i,y2);

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Adam Danz 2018-7-13

编辑：Adam Danz 2018-7-13

在 MATLAB Online 中打开

Your example doesn't work.

What do you mean by aligning their mean values? Do you mean for each line you'd like to subtract the mean?

x = x-mean(x); 
y = y-mean(y);

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Answer 1

Image Analyst 2018-7-14

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https://ww2.mathworks.cn/matlabcentral/answers/410298-if-i-have-three-graphs-and-i-want-to-place-them-over-one-another-so-that-their-mean-values-align-an#answer_328848

在 MATLAB Online 中打开

Try this:

x1=[1:0.03:500];
y1 = x1.^4;
x2 = [100:0.01:600];
y2 = x2.^2+30;
plot(x1,y1, 'r-', 'LineWidth', 2);
hold on;
plot(x2,y2, 'b-', 'LineWidth', 2);
grid on;
xAll = [x1, x2];
yAll = [y1, y2];
[coefficients, S, mu] = polyfit(xAll, yAll, 1)
numPoints = max([length(x1), length(x2)])
fittedX = linspace(min(xAll), max(xAll), numPoints);
fittedY = polyval(coefficients, fittedX, S, mu);
plot(fittedX, fittedY, 'g-', 'LineWidth', 2);
legend('y1', 'y2', 'linear fit y', 'location', 'north');

Is that what you're thinking of? Note that because you have more of the flatter curve points, it's pulling down the "average" line curve. If you don't want that you can use interp1 to resample to have them both have the same number of points and same starting and ending x values.