use least squares to create a function that performs regression for v = a*(x/(x+b)) and output a, b, and r^2 in matlab

To use least squares to perform regression for the function v = a*(x/(x+b)) and output the values of a, b, and r^2 in MATLAB, you can follow these steps:

  1. Define your independent variable x and dependent variable v as input data.
main.m
x = [x1, x2, x3, ..., xn]; % input independent variable data
v = [v1, v2, v3, ..., vn]; % input dependent variable data
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  1. Create a function handle for the regression model v = a*(x/(x+b)).
main.m
model = @(x, params) params(1) * (x ./ (x + params(2)));
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  1. Define an initial guess for the parameter values a and b.
main.m
initialGuess = [initialA, initialB];
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  1. Use the lsqcurvefit function to perform least squares regression and estimate the parameter values a and b.
main.m
params = lsqcurvefit(model, initialGuess, x, v);
a = params(1);
b = params(2);
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  1. Calculate r^2 to measure the goodness of fit.
main.m
% Calculate the predicted values using the estimated parameters
v_predicted = model(x, params);

% Calculate the total sum of squares (SST)
sst = sum((v - mean(v)).^2);

% Calculate the residual sum of squares (SSE)
sse = sum((v - v_predicted).^2);

% Calculate r^2
rSquared = 1 - (sse / sst);
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  1. Output the values of a, b, and r^2.
main.m
disp(['a = ', num2str(a)]);
disp(['b = ', num2str(b)]);
disp(['r^2 = ', num2str(rSquared)]);
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Note that you need to replace x1, x2, ..., xn and v1, v2, ..., vn with your actual data points.

Make sure you have the Curve Fitting Toolbox installed in MATLAB to use the lsqcurvefit function.

I hope this helps!

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