for loop for MATLAB code to calculate Mean value : I have an excel sheet of 41 columns and 513 rows. I want to use a loop which will calculate the mean of 4 columns. The interval is i = 2:4:41. I need help with writing down the loop. 

for i = 2:4:41
*the formula for the mean calculation, V()=V()/41;*

Need help with the **. Thank you