Errors that occur during a mentos and Diet Coke experiment?

The errors that may occur are:

Differences in height that mentos is dropped from (if performed more than once, when comparing), If you accidentally shook the coke before performing the experiment and different flavours of mentos being used without noticing (eg. if using a fruit flavour pack, using all the flavours instead of using just one). I hope this makes sense and helps :)