#Pseudocode/pseduoalgo - whatever you call it

@arr=<FILE>; #slurp the file into array

for $line (@arr) #Loop through the file
{
     #Do you need to chomp the line?
     #Do you need to split the line on comma delimiter?
     #Do you need a mean calculation formula here?
     #Do you need a std dev formula here?
     #Do you need to print the calculated values in new file?
}