1. In the course of the MRSA surveillance, the public health department found that the prevalence of MRSA colonization increased to 1 in 200 for people who recently visited a health care facility. You went to the hospital to visit your sick aunt last week. What is the new probability that you have MRSA colonization?

2.Given the following information, what is the probability that a woman has breast cancer if she has a positive mammogram result? (2 points)

1. One percent of women over 50 has breast cancer
2. Ninety percent of women who have breast cancer test positive on mammogram
3. Eight percent of women will have false positives.

3.For a given exam question, sixty percent of the students know the correct answer. However, there is a 15% chance that a student picked the wrong answer even if she/he knows it and there is a 25% chance that a student does not know the answer, but guessed it correctly. If a student got the answer correct, what is the probability that she/he actually knows the answer? (2 points)

4.A clinical test, designed to diagnose a specific illness, comes out positive for a certain patient. We know that the test is 79% reliable (misses 21% of cases), on average the disease affects 1% of the population in the same age group as the patient and the test has a 10% false positive rate. What is the probability that the patient actually has this illness? (2 points)