Say, in a field the grass can be wet due to sprinkler and rain. If it rains, the sprinkler is generally off. The probabilities of raining any day, sprinkler being on given it is raining, and observing the wet grass given rain and sprinkler conditions are summarized in Fig. 1.

Find the probability of the grass to be dry if it does not rain with Bayes rule.

SPRINKLER 1 MIN T F SPRINKER MIN 0.6 0.90 0.2 0.0 0.01 GRASS WET GHSS WET T F SPRINKLER FIN 0.0 0.8 0.9 0.99 10 0.2 0.1 0.01 T Fig. 1 SPRINKLER T F RAIN T F RAIN SPRINKLER RAIN 0.2 08 F 0.4 0.01 0.6 0.99 GRASSW ET GRASS WET SPRINKLER RAIN T F F F T F 0.0 0.8 0.9 0.99 1.0 0.2 0.1 0.01 F T T T