We have identified a SNP that is associated with the quantitative trait in the discovery study (n = 1500). Now, we wanted to replicate this SNP association. What is the sample size that is required for the replication study (to reach 80% power)? The beta value for this SNP is 0.02 and it has 48% allele frequency (minor).
Can we use the 2-stage power calculation for this purpose?
Thanks in advance.
Kind regards, Ezhil