For kinetics of a reaction lab degree of tolerance...

We used an ordinary stop watch with 2 digits for seconds and 2 digits for miliseconds (lik 24 sec and 10 milisec)

would the degree be like +/- 0.01 sec or would it be +/- 1.00 sec
I was thinking that although mathematically +/- 0.01 sec makes sense, our reaction time would make a bigger difference.
Which is right?

Since you can actually read the stopwatch to hundredths of a second, you should express times as +/- 0.01 sec.