Tic and Toc Function

For my engineering class I had to make a while loop to find the average of a data set and use tic/toc to time the process. My code is posted below but for some reason when I run tic/toc it says it takes 7 seconds. I'm just not sure this is right because a few of my classmates told me theirs was around 1 second and when I time it myself it doesn't take 7 seconds. If someone could tell me where my error is if there is one I would appreciate it!

[Amanda Wojcik]

sorry here is my code!

 y=load('ClassSDPprep_watts.txt');
tic;
sum=0;
i=1;
while i<=length(y);
    sum=sum+y(i);
    i=i+1;
end
Average
time=toc

[Walter Roberson]

We recommend against using a variable named "sum", as it is almost certain that at some point you will have a variable with that name at at time that you want to use the sum() function.

[Walter Roberson]

You have not given us any information about what Average does.

You could improve your performance by calculating length(y) once before the loop and using that variable. With your current code it needs to recalculate length(y) every step.

[Amanda Wojcik]

Ok thank you that makes sense! When I copied the code I forgot to include average=sum/length(y)