Table 1. Effects of the application of retinoic acid on rats and thymuses weight.

	Experimental group (Mean±SD)	Control group (Mean±SD)	Level of significance
One-day-old-rats
Weight of the rats (g)	5.90±1.04	7.15±0.84	P=0.054 ns
Weight of thymuses (g)	0.07±0.05	0.06±0.02	P=0.271 ns
Seven-day-old rats
Weight of the rats (g)	12.94±2.63	16.38±0.83	P=0.016*
Weight of thymuses (g)	0.07±0.02	0.09±0.02	P=0.093 ns
Fourteen-day-old rats
Weight of the rats (g)	29.37±6.60	30.67±6.49	P=0.714 ns
Weight of thymuses (g)	0.14±0.06	0.18±0.05	P=0.175 ns
Twenty-one-day-old rats
Weight of the rats (g)	48.19±14.85	53.59±4.63	P=0.337 ns
Weight of thymuses (g)	0.31±0.10	0.35±0.04	P=0.396 ns

SD, standard deviation; ns, not significant;

^*significant.