I am a high school student in the process of writing his report in physics. I did the experiment for simple pendulum and different lengths however, I measured the standard deviation in the time period for different lengths. At the end of the report, it is suggested to compare your results with another report but I thought a creative idea would be to measure the uncertainty using $$\frac{\Delta T}{T_0}=\frac{1}{2} \times \frac{\Delta L}{L_0}$$
Anyway, I figured out doing it this way then take the percentage of both uncertainties to show how accurate is my experiment.
Using 0.03 m length and addition in uncertainty for ruler and micrometer gives (5.05 x 10^-4). According to the standard deviation for (0.03 m), I got standard deviation of (0.09119298) and using the equation, I got a value of uncertainty of (8.416 x 10^-4).
However finding the percentage wasn’t right. Did I do something wrong? Is it possible to do this?
Thanks a lot and I will be waiting for your help.