Ok, I am confused as to how we determine the expected number in the chi square equation: sum of (observed-expected)^2/expected. Can someone explain to me the concept of this. How do you find the expected number? Give examples too please, My guess is that like the expected is like the the total progeny, and the ratio they are closest too, like for example if the ratio they are most similar to is 1:1:1:1. You add 1+1+1+1=4 so it's 1/4 and you multiply that by the total number to get the expected number. Or for example if the ratio looks to be close to 9:3:3:1. you multiply the highest ratio number by the total (which is 16) so 9/16.