Table 4. Average score on the PTSSC-15 depression subscale (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	3.9	4.1	119	3.4	3.8	111	3.5	3.3	95	Gender × Period	2.184	N.S.
	Girls	3.8	3.8	127	3.8	3.9	127	2.5	2.8	123	Period	3.312	<0.05
											Gender	0.709	N.S.
1st–3rd grade	Boys	4.7	4.0	1866	4.5	4.0	1632	3.5	3.5	1592	Gender × Period	0.570	N.S.
	Girls	4.7	4.1	1736	4.4	3.9	1581	3.3	3.3	1615	Period	108.5	<0.0001
											Gender	1.711	N.S.
4th–6th grade	Boys	5.1	4.6	1975	4.7	4.4	1792	4.1	3.7	1854	Gender × Period	1.235	N.S.
	Girls	5.2	4.5	1973	4.6	4.3	1798	3.9	3.5	1807	Period	70.37	<0.0001
											Gender	0.705	N.S.
7th–9th grade	Boys	6.2	4.8	1979	5.7	4.6	1767	4.7	3.8	1893	Gender × Period	1.080	N.S.
	Girls	6.9	4.9	1864	6.3	4.7	1789	5.1	3.9	1833	Period	130.7	<0.0001
											Gender	44.60	<0.0001

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