I am trying to present sample size determination based on determining a certain difference between two proportions and the power of the test. As I understand it, my calculation requires both z-alpha and z-beta. From past experience I am aware that z-beta for a power of 90% is 1.282 and z-beta for a power of 80% is 0.842.
However, I am not sure what z-beta is for a power of 70%. I would love to use this for my study as well and also would am curious as to if anyone can provide a table for these values or a way to find this in R. Thanks!