# Thread: calculate the standard error of the mean

1. ## calculate the standard error of the mean

To whom it may concern:

I have a cognition experiment which has 10 subjects. Each subject performs 400 trials. My advisor wants me to calculate the standard error of the mean using trial numbers (i.e. 400) in the denominator of the formula (i.e. sample standard deviation divided by square root of number of observations). In my understanding, I think I should use 10, instead of 400, in the denominator. I am really confused. Thank you for helping.

Best Regards
Jay Chen

2. ## Re: calculate the standard error of the mean

What is the null hypothesis that you and your advisor are testing?

3. ## Re: calculate the standard error of the mean

Dear Dragan:

Thank you for reply. For each subject, we calculate a metric using 400 trials. The reason that I want to calculate the standard error of the mean is that I want to plot mean value of the metrics for all 10 subjects as the column chart . The null hypothesis is mean value of the metrics is zero.

Best Regards
Jay Chen

 Tweet