I can work the following with a tree diagram but not with simultaneous equations:
75% of patients who have cancer and 10% of normal patients (who do not have cancer) are diagonised with cancer by a MRI. If 15% of a population have cancer, what is the probability of patients who are digonised with cancer by a MRI that really do have cancer?
Using a tree diagram, i get probabilty of patients being diagonised which actually have cancer
= (0.15 * 0.75)/ [(0.15 * 0.75) + (0.85 * 0.1)]
Thanks in advance,