When a doctor observes your symptoms and tells you that you have flu, she is reasoning?

When a doctor observes the symptom of a patient and tells that he or she is likely having a flu, the reasoning she or he used is likely from the effect to cause. The reasoning from effect to cause is having to check on the cause in order to produce or come out with the effect in which the symptoms is the cause of the flu, in which the flu is the effect.

i need an image of the diagram