MATLAB: I am trying to implement probality density function on an image but i can not understand how to calculate data, mu and sigma.here is the code is it right to take data as pixl value

Question

 k = imread('2.jpg');
 img2=rgb2gray(k);
sigma =?;
mu=?
pd = makedist('Normal',mu,sigma);
data = img2(I,j)
y = pdf(pd,data);
figure,
plot(data,y,'LineWidth',2)

Answer 1

mu = mean2(img2);
sigma = std2(img2);