how to calculate the f distribution in matlab

To calculate the F distribution in MATLAB, you can use the functions fpdf and fcdf for the probability density function (PDF) and the cumulative distribution function (CDF), respectively.

The syntax for fpdf is:


main.m
y = fpdf(x,v1,v2)
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where x is the vector of x-values, and v1 and v2 are the degrees of freedom parameters for the numerator and denominator, respectively.

The syntax for fcdf is:


main.m
y = fcdf(x,v1,v2)
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where x is the vector of x-values, and v1 and v2 are the degrees of freedom parameters for the numerator and denominator, respectively.

Here is an example code that calculates and plots the F distribution for different values of v1 and v2:


main.m
v1 = 3;
v2 = [5, 10, 20];
x = 0:0.1:4;

% Calculate PDF
pdf = zeros(length(v2), length(x));
for i = 1:length(v2)
    pdf(i,:) = fpdf(x, v1, v2(i));
end

% Calculate CDF
cdf = zeros(length(v2), length(x));
for i = 1:length(v2)
    cdf(i,:) = fcdf(x, v1, v2(i));
end

% Plot PDF and CDF
figure;
subplot(1,2,1);
plot(x, pdf(1,:), x, pdf(2,:), x, pdf(3,:));
legend('v2=5', 'v2=10', 'v2=20');
title('F Distribution PDF');
xlabel('x');
ylabel('f(x)');
subplot(1,2,2);
plot(x, cdf(1,:), x, cdf(2,:), x, cdf(3,:));
legend('v2=5', 'v2=10', 'v2=20');
title('F Distribution CDF');
xlabel('x');
ylabel('F(x)');
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