I NEEDED HELP
on key concept

My results provide evidence of variations within the classroom since everyone's results do vary and show different lengths. On top of that, the results show the diversity between the class and it represents the difference of the measurments thorughout the classroom population.

I don’t exactly know what you mean, but I think on the key concept it is trying to tell you to find your classmates forearm length and find the average of the class, and then see how your arm length varies to your classmates.