Desert lizards (Dipsosaurus dorsalis) regulate their body temperature by basking in the sun or moving into the shade, as required. Normally the lizards will maintain a daytime temperature of about 38°C. When they are sick, however, they maintain a temperature about 2o to 4o higher -that is, a "fever." In an experiment to see whether this fever might be beneficial, lizards were given a bacterial infection; then 36 of the animals were prevented from developing a fever by keeping them in a 38o enclosure, while 12 animals were kept at a temperature of 40o. The following table describes the mortality after 24 hours. How strongly do these results support the hypothesis that fever has survival value? Use Fisher's exact test against a directional alternative. Let α = 0.05.

38 40 Died 18 Survived 18 10 Total 36 12