Mean-variance diagrams of the number of malaria vectors collected per village (Panel A), per mission (Panel B), and per village-mission (Panel C).

<p>Panel D shows a bar diagram of the distribution of mosquito counts at each collection site (the scale of the X-axis was limited to 14). On panels A, B and C: the dotted lines represent a linear link between the means and the variance ( with = 7.4, 6.48 and 5.9 respectively); the curves represent a quadratic link between mean and variance ( with = 4.4, 8.9 and 1.1 respectively).