Distribution of Sch-FRI episodes by schools and classrooms from weeks 26 to 34. A) School level rates of FRI episodes per 100 children; error bars denote 95% confidence intervals from a Poisson distribution. B) Distribution of classroom level rates of FRI episodes per 100 children for 124 primary and 157 secondary school classrooms, in light and dark grey respectively. Dashed line gives the expected distribution based on the combined average of 9.2 FRI episodes per classroom.
Soh et al. BMC Infectious Diseases 2012 12:336 doi:10.1186/1471-2334-12-336