The box plot is useful for comparing the quartiles and variation of quantitative variables. In a box plot, lower and upper ends of a box (the hinges) are the first (Q1) and third quartile (Q3), and the middle horizontal line represents the median (Q2) of the data. Outliers of the data are shown by the whiskers of the boxes, when data falls above 1.5 * IQR, where the inter-quartile range IQR = Q3 - Q1.
The monthly dengue incidence data for each administrative district presented in the website of the Epidemiology Unit, Ministry of Health, Sri Lanka are used for the analysis.
Administrative units of Sri Lanka
Sri Lanka is divided into 9 provinces as the first layer of administrative units. The 9 provinces are Central Province(CP), Eastern Province(EP), North Central Province(NC), Northern Province(NP), North Western Province(NW), Sabaragamuwa Province(SG), Southern Province(SP), Uva Province(UP) and Western Province(WP).
