I have a problem that I need help with, please! I have results of a pre/post test and I was asked to find the standard deviation for that particular question. Here is what the output looks like: enter image description here
30 users filled out the test and they either got it correct, or they got it incorrect.
I am having trouble figuring out how to solve this. Any help would be GREATLY appreciated!!! Thank you!!!!
This website has a good simple definition on how to calculate the standard deviation.