Marginalised groups are all those excluded from governmental policy and access to education including: women and girls, indigenous peoples and minorities, persons with disabilities, persons with HIV / AIDS, child labourers, persons in detention, migrants, refugees and IDPs, and persons living in poverty (Source: Audrey Chapman (2007) Development of Indicators for Economic, Social and Cultural Rights: The Rights to Education, Participation in Cultural Life and Access to the Benefits of Science: p.145)

Percentage of schools with potable water is the share of schools at a given level of education with a drinking water facility or water delivery point that is designed to protect water from external contamination, particularly of fecal origin. Examples of potable drinking water facilities include: pipe-borne water, protected wells, boreholes, protected spring water and rainwater

Percentage of schools without electricity is the share of schools with no access to permanent sources of electrical power, for example grid / mains connection, wind, water, solar, permanently fuel-powered generator, etc.

Percentage of schools without toilets is the share of schools at a given level of education without a pit latrine, an improved pit latrine, a flush toilet, a pour-flush toilet or a composting toilet

Means to pursue their educational activities would include access to regular classes with qualified teachers, access to books, etc. 

The legal minimum age of military recruitment is the age at which a person is permitted to enlist or be conscripted and take part in hostilities