The global prevalence rate, for ADHD, varies considerably from a 7% rate in Japan to a 20% prevalence rate in Ukraine. What factors contribute to this variance?
◦ The variance is explained by differences in the definition and in procedures for collecting data.
◦ The variance is explained by the number of students enrolled in schools in the country.
◦ The variance is explained by the number of special educators in the country.
◦ The variance is explained by the level of economic development of the country.