Bednets and malaria. In a randomized controlled trial in Kenya, insecticide-treated bednets were tested as a way to reduce malaria. Among 343 infants who used the bednets, 15 developed malaria. Among 294 infants not using bednets, 27 developed malaria (based on data from

“Sustainability of Reductions in Malaria Transmission and Infant Mortality in Western Kenya with Use of Insecticide-Treated Bednets” by Lindblade et al., Journal of the American Medical Association, Vol. 291, No. 21).

Assuming that the bednets have no effect, there is a probability of 0.015 of getting these results by chance. Do the results appear to have statistical significance? Do the bednets appear to be effective?