Statistical Power = 1 - β, the probability of detecting an effect when it truly exists. Typically, power ≥ 0.80 is desired.
Formula based on normal distribution: Power = Φ(z - z_α), where z = d × √(n/2), d is effect size, n is sample size per group.
Power depends on three factors: larger sample size → higher power; larger effect size → higher power; larger α → higher power.