A Comparative Study of Palatal Rugae Patterns among Igbo and Ikwerre Ethnic Groups of Nigeria: A University of Port Harcourt Study

Table 1

-test of proportionality difference in rugae pattern distribution between Ikwerre and Igbo males.

Pattern	Tribe	Obs. population ()	Sampled population ()	Obs. proportion	-value (calculated)	critical	value (obs.)	Inference
Wavy	Ikwerre	119	335	0.356	−3.98	1.96	<0.0001	Significant difference in proportions *
	Igbo	161	312	0.511
Curvy	Ikwerre	151	335	0.451	4.53	1.96	<0.0001	Significant difference in proportions *
	Igbo	87	312	0.279
Circular	Ikwerre	12	335	0.036	−1.49	1.96	0.136	No significant difference in proportions
	Igbo	19	312	0.061
Straight	Ikwerre	33	335	0.099	1.76	1.96	0.078	No significant difference in proportions
	Igbo	19	312	0.061
Converging	Ikwerre	7	335	0.021	−0.89	1.96	0.373	No significant difference in proportions
	Igbo	10	312	0.032
Diverging	Ikwerre	13	335	0.039	−0.77	1.96	0.441	No significant difference in proportions
	Igbo	16	312	0.051

The asterisks were used to demonstrate values with significant difference.