Statistical analysis
Sample size was based on earlier studies, in which the priori power analysis was undertaken for an unpaired Student’s t-test, α at 0.05 and β at 0.2, i.e., Power (1 − β) or 0.8. A difference of 0.75 mm in the mean cement penetration between each group was determined to be clinically relevant. With a two-sided test, 58 patients were required. With a one-sided test, a loss of 12 patients could be tolerated [