Table 4. The Relationship Between Using Cell Phones After Lights are Out and Tiredness.

Type Cell Phone Use After Lights Are Out	Logistic Regression			P Value
	OR	95% Confidence Interval
		Upper	Lower
Sending or receiving text messages	.648	.99	.42	.04
Phone calls	.508	.91	.28	.024
Any use	.57	.90	.36	.01