1. Elvis Presley had a twin brother that died at birth. What is the probability that Elvis was an identical twin? Given twins occur in 1.9% of births and identical twins make up 8% of the total twins. Hint: the gender of the twin is the key factor to solve the problem.

2.What is the probability of a patient in your clinic having kidney disease if they are diabetic p(K/D)? You know that there is a 10% rate of kidney disease in your clinic (prevalence) p(K) and 5% of your patients are diabetic p(D). You also know that 7% of your patients with kidney disease are diabetic p(D/K) (probability that patient is diabetic given that they have kidney disease).

3.Your state is conducting a random surveillance for the MRSA. You are selected to have a nasal swab to see if you are colonized with MRSA. It is thought that 1 in 10000 people are colonized with MRSA in your state (prevalence). The swab is 99% sensitive, in the sense that the probability of a false positive is 1%. The probability of a false negative is zero (specificity is 100%). You test positive. What is the new probability (predictive value) that you have MRSA colonization?