Fig. 3

Distribution of the total difficulties score by gender in the child sample and the adolescent sample. Note. Distribution of the total difficulties score by gender in the child sample (on the left, according to the Children’s Sleep Habits Questionnaire [CSHQ], score range = 33−99, n = 855) and the adolescent sample (on the right, according to the Sleep Self Report [SSR], score range = 18−54, n = 1,047). Shaded areas show split violin plots of the density function, with inserted boxes indicating the first and third quartile and the median, and with the point indicating the arithmetic mean. The displayed p-values are derived from linear regression analysis. Scores above the cut-off value indicate problematic amounts of sleep-related difficulties