To calculate the expected record of a replication or quasi-replication study, we assume that the SNP is non-null for both phenotypes. (This is analogous to a standard power calculation for a single phenotype, in which the SNP is assumed to be non-null.) Under this assumption, β̂1 and β̂2 are jointly normally distributed, implying that the conditional distribution of β̂2 given β̂1 is
