Table 2.

Comparison of age (years) of patients before treatment ($\overline{X}\pm S$)

Group	$n$	18$\sim$	30$\sim$	40$\sim$	50$\sim$65	Minimum age	Maximum age	$\overline{X}\pm S$
Treatment	40	5	5	13	17	20	65	51.079 $\pm$ 9.137
Control	40	4	6	12	18	23	64	48.877 $\pm$ 10.525