On the probability of being sick, when tested positive

*On the probability of being sick, when tested positive*

**From the German book: Bornholdt, Dubben – ”Der Hund der Eier legte”. After your return from an exotic place you are afraid to be infected with a nasty disease that infects every 1,000th tourist. Healing prospect is good if detected and treated early. You are tested positive.**


**Accuracy of the screening test:**

When tested positive, the chances to really have the disease are 4.7 percent (47 out of 1,000 persons with positive testresult are truly diseased)

*On the probability of being sick, when tested positive*

**There is an easy-to-administer, harmless and low priced test that simply classifies everybody as diseased. What is the probability of truly having the disease when classified positive under this test?**

The disease prevalence

*On the probability of being sick, when tested positive*

**From the German book: Bornholdt, Dubben – ”Der Hund der Eier legte”. After your return from an exotic place you are afraid to be infected with a nasty disease that infects every 1,000th tourist. Healing prospect is good if detected and treated early. You are tested positive.**

**Accuracy of the screening test: 99 out of 100 diseased are detected 98 out of 100 non diseased are detected What is the probability that you have the disease?**

When tested positive, the chances to really have the disease are 4.7 percent (47 out of 1,000 persons with positive testresult are truly dis- eased)

*On the probability of being sick, when tested positive*

**There is an easy-to-administer, harmless and low priced test that simply classifies everybody as diseased. What is the probability of truly having the disease when classified positive under this test?**

The disease prevalence