. 2014 Sep 8;2014:123925. doi: 10.1155/2014/123925

Table 2.

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

Pattern	Tribe	Obs. population (n)	Sampled population (N)	Obs. proportion	z-value (calculated)	\|z\| critical	P value (obs.)	Inference
Wavy	Ikwerre	117	289	0.405	−4.7572	1.96	<0.0001	Significant difference in proportions ∗
Wavy	Igbo	188	314	0.599	−4.7572	1.96	<0.0001	Significant difference in proportions ∗

Curvy	Ikwerre	99	289	0.343	2.1791	1.96	0.02926	Significant difference in proportions ∗
Curvy	Igbo	82	314	0.261	2.1791	1.96	0.02926	Significant difference in proportions ∗

Circular	Ikwerre	14	289	0.048	−0.9672	1.96	0.33204	No significant difference in proportions
Circular	Igbo	21	314	0.067	−0.9672	1.96	0.33204	No significant difference in proportions

Straight	Ikwerre	34	289	0.118	3.1373	1.96	0.00168	Significant difference in proportions ∗
Straight	Igbo	15	314	0.048	3.1373	1.96	0.00168	Significant difference in proportions ∗

Converging	Ikwerre	7	289	0.024	0.7289	1.96	0.4654	No significant difference in proportions
Converging	Igbo	5	314	0.016	0.7289	1.96	0.4654	No significant difference in proportions

Diverging	Ikwerre	18	289	0.062	3.5282	1.96	0.00042	Significant difference in proportions ∗
Diverging	Igbo	3	314	0.01	3.5282	1.96	0.00042	Significant difference in proportions ∗

The asterisks were used to demonstrate values with significant difference.