# how to interpret reading decision tree result from ctree() in r?

After running ctree(model)

My result look like this below :

1) iv == (a,b,c) ; criterion = 1 , statistic = 200
2) iv2 == (x,y) ; criterion = 0.99 , statistic = 32
3) iv3 < 30 ; criterion = 0.91 , statistic = 35
4) weight = 100


I am new to this , but can anyone please explain to me say my total volume is 500

I know that that node (4 ) given me volume of 100 , but what exactly is criterion = 1 and statistic = 200 means ?

Thank you