Sample size calculation
We used the following formula to calculate the required sample size [μμσ = variance (SD) for the mean of anticipatory grief score which was considered 23.1 (the average SDs reported for anticipatory grief score in the 2 groups of Fowler et al. study [a = conventional multiplier for alpha = 0.05 that was 1.96b = conventional multiplier for power = 0.80 that was 0.842Overall, based on the formula and given a 10% drop-out in each group, we needed a sample size of 50 caregivers for each intervention group.