data class marks 10 15 20 25 30 35 40 45 observed frequencie

data class marks	10	15	20	25	30	35	40	45
observed frequencies	10	13	65	87	90	23	20	8
expected frequencies	6.5	22.8	54.6	82.7	78.9	47.3	17.8	5.4

Compute the Mean and Standard Deviation for grouped data from given frequencies and class marks passed as parameter lists. Design and write two MATLAB m-file functions that compute these two statistical measures. These two functions should accept as input parameters, two lists observed from the sample: A list of grouped data class marks x_cm, and a list of frequencies f_obs. Use grouped data formulas, e.g. for the Grouped-Mean use sigma(xf)/sigma(f). Inside of these functions use the sum () function and array operations, careful, in the SD function sigma (x^2f) rightarrow sum (x.^2. *f) but (sigma (xf))^2 rightarrow sum (x. *f)^2 Observe the placement of the square operation and the use of^instead of^Print the results with a fprintf () statement inside each of these functions.

Solution

%Create first file named mymean.m, and paste below code in it (please give file names as I said, otherwise it wont work)

function m = mymean(x_cm,f_obs)
m = sum(x_cm*f_obs\')/sum(f_obs);
end

% create second file named SD.m and paste below code in it

function sd = SD(x_cm,f_obs)
m = mymean(x_cm,f_obs);
sd = sqrt(sum(((x_cm - m).^2)*f_obs\')/sum(f_obs));
end

%create one more file drive.m, where we call above functions.

marks = [10,15,20,25,30,35,40,45];
freq = [10,13,65,87,90,23,20,8];
final_mean = mymean(marks,freq);
final_SD = SD(marks,freq);
fprintf(\'%s%f\ \',\'Mean is \', final_mean);
fprintf(\'%s%f\ \', \'Standard Deviation is \',final_SD);

%SAMPLE OUTPUT

%Mean is 26.693038
%Standard Deviation is 7.230216