Question

Please solve the following problem for MATLAB

Write a user-defined function that calculates the average and the standard deviation of a list of numbers. Use the function to calculate the average and the standard deviation of the following list of grades : 80 75 91 60 79 89 65 80 95 50 81

Answer 1

The following is the MATLAB code for above question. It has met all the requirements stated in the question.

grades = [80 75 91 60 79 89 65 80 95 50 81];
function [m,sd] = meanandstd(x)  %create a user defined function to calculate mean and standard deviation without using inbuilt functions
    n = length(x);  %store the length of grades in k
    s = 0;  %declaring sum as s, since sum is an inbuilt function
    for i = 1: n
        s=s+x(i);
    end
    m = s/n; %calculate mean
    for i = 1: n
        sd = ((x(i)-m).^2); %calculate standard deviation
        sd = sqrt((sd)/n);
    end
end
[Mean,Standard_Deviation] = meanandstd(grades)

I am also attaching the output and code screenshot for your reference. It will help you to cross check if any error.

Output and code screenshot:

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