this study on pre-schoolers N = 44 (%)

health survey on pre-schoolers N = 931 (%)

z

p

before 9 pm

2 (4.5)

120 (12.9)

−1.635

0.102

9 - 10 pm

29 (65.9)

533 (57.3)

1.136

0.256

after 10 pm

13 (29.6)

233 (25.0)

0.674

0.500

N.A.

0 (0.0)

45 (4.8)

−1.488

0.137