selection of one parameter for correlation coefficient

Suppose, I have 100 rows of P and Q, and 20 rows of data make a group. Average of each group gives new set of data points (total 5 for each). I want to calculate correlation of coefficient for each group. But it gives 2x2 matrics. how can I select one value for each data 20 row?

P = [1:100];

Q = [1:100];

index = 20;

new_group = zeros(5,3); % average of each 20 row of P (=P_av), Q (=Q_av), and correlation of coefficient for each 5 groups of P and Q

A = randn(10,1);

B = randn(10,1);

R = corrcoef(A,B)

Result: R = 2×2

1.0000 0.4518

0.4518 1.0000 %

%how to select one (here 0.4518) for each group?

Thanks a lot in advance.

Answer 1

[Abhishek Chakram]

Hi Mst Ismita Tasnim,

It is my understanding that you are facing difficulty in writing the code for selecting a particular parameter for correlation coefficient. Here’s an example for the same:

P = [1:100];
Q = [1:100];
index = 20;
new_group = zeros(5,3); % average of each 20 row of P,Q,and the correlation coefficient for each 5 groups of P and Q

% Loop through each group
for i = 1:5
    % Select the rows for the current group
    start_index = (i-1)*index + 1;
    end_index = i*index;
    P_group = P(start_index:end_index);
    Q_group = Q(start_index:end_index);
    
    % Calculate the average of P and Q for the current group
    P_av = mean(P_group);
    Q_av = mean(Q_group);
    
    % Calculate the correlation coefficient for the current group
    R = corrcoef(P_group, Q_group);
    correlation_coefficient = R(1, 2); % Select the value at (1, 2) position
    
    % Store the results in the new_group array
    new_group(i, :) = [P_av, Q_av, correlation_coefficient];
end

Best Regards,

Abhishek Chakram