We can estimate conservatively the possible contact-level-hours with random contacts by taking each contact of 1 minute duration and of level 2 yielding 2 per-person-per-day for 9 12th graders, 4 for 7th graders, and less than 1 for 5th graders.
A total of 62 7th graders took part in the study, and significant findings were revealed.
Group discussions with approximately 100 7th graders at a number of low-income schools showed that virtually all of these students already have high expectations for attending college.
Secondary 1 students (7th graders; N = 275) were surveyed with 24 items about their academic self-concepts in physics, English, and math in two components (cognitive and affective), and their respective achievement scores were recorded over two time points.
Random contacts per-person-per-day in middle and high-school passing periods far exceed all other public activities at 98 for 7th graders and 44 45 for 9 12th graders.
From 2001 to 2008 the proportion of 6th graders with a high level of screen time activity decreased more than the proportion of 7th graders, by 15 and 5 percentage points, respectively (Table 2).
A longitudinal multilevel study design was adopted, which included 978 5th to 7th graders from four Chilean schools.
Tests of interaction hypotheses use data from the Family Transitions Project, a longitudinal study of 7th graders followed for 5 years.
