Figure 4

Plots of malaria prevalence against fourteen potential explanatory variables. Scatter – and box plots of candidate environmental explanatory variables used in step-wise procedures. Malaria prevalence in 1 to 14 year old children, Botswana, 1961/62, is shown on the Y axis on a logit scale. (A) annual maximum rainfall (mm); (B) winter (April – October) total rainfall (mm); (C) rainfall concentration (%); (D) winter (April – October) mean temperature (°C); (E) annual maximum temperature (°C); (F) temperature proportional standard deviation (°C); (G) elevation (m); (H) annual maximum NDVI; (I) NDVI standard deviation; (J) summer (December–March) mean vapour pressure (hPa); (K) vapour pressure standard deviation (hPa); (L) log distance to permanent water (m); (M) land cover: dry/low risk, moist/high risk areas; (N) start month of survey.