highly significantP < 0.001
The following statistical formulas were used: (1) Chi square test: (1) χ 2 = Σ ( O − E ) 2 E , where O is observed frequency and E is expected frequency and (2) level of significance: “ P ” is level of significance P > 0.05 is not significant, P < 0.05 is significant, P < 0.01 is highly significant, and P < 0.001 is very highly significant. 3.