Table 5. Average PTSSC-15 PTSD score (by grade, gender, or period).

Grade group	Gender	Months after disaster
		2011 After 8 months			2012 After 20 months			2013 After 30 months				F	P value
		M	SD	N	M	SD	N	M	SD	N
Kindergartners	Boys	9.3	7.7	119	8.2	7.1	111	9.2	7.9	95	Gender × Period	1.196	N.S.
	Girls	9.4	8.0	127	8.4	7.4	127	7.5	6.5	123	Period	1.468	N.S.
											Gender	0.683	N.S.
1st–3rd grade	Boys	10.4	7.9	1866	9.9	7.8	1632	9.4	7.7	1592	Gender × Period	1.230	N.S.
	Girls	11.1	7.9	1736	10.0	7.7	1581	9.8	7.8	1615	Period	18.99	<0.0001
											Gender	6.558	N.S.
4th–6th grade	Boys	12.1	9.3	1975	11.1	8.7	1792	11.5	8.8	1854	Gender × Period	3.523	<0.05
	Girls	13.7	9.7	1973	11.6	8.8	1798	12.4	8.9	1807	Period	27.77	<0.0001
											Gender	34.09	<0.0001
7th–9th grade	Boys	12.8	9.3	1979	11.7	8.7	1767	11.9	11.9	1893	Gender × Period	0.339	N.S.
	Girls	15.8	9.7	1864	14.4	9.3	1789	15.0	15.0	1833	Period	12.76	<0.0001
											Gender	202.1	<0.0001

M, mean; SD, standard deviation; N, number of cases; N.S., not significant.