1. A city contains 100,000 people (45,000 males and 55,000 females), and 1,000 people die per year (600 males and 400 females). There were 50 cases (40 males and 10 females) of lung cancer per year, of whom 45 died (36 males and 9 females). Compute:

a. Crude mortality rate
b. Sex-specific mortality rate
c. Cause-specific mortality rate for lung cancer
d. Case fatality rate for lung cancer
e. PMR for lung cancer

2. Two simple and inexpensive screening methods have been developed to identify individuals with HIV infection at routine medical check-ups. To study the sensitivity and specificity, both methods were tested on 12860 persons who underwent a simultaneous and thorough clinical examination that was considered to give an accurate diagnosis. There were 1900 cases of disease as diagnosed by clinical methods. The Screening test #1 was positive for a total of 1000 people, including 800 with active HIV infection. The screening method #2 was positive for 2444 individuals. This method also detected 800 individuals diagnosed with active HIV as positive.

a) Calculate the sensitivity of each screening method.

b) Calculate the specificity of each screening method.

C) What is the positive predictive value of each screening method?

d) what is the negative predictive value of each screening method?

3. with respect to the above question, which screening method would you recommend? Give your reason for this recommendation.

4. In a mass screening aimed at early diagnosis of HIV infection in West Chester, PA, the screening method you recommended in question # 3 above is used. Of 25000 individuals attending the screening, 6843 were found to be positive. Calculate the prevalence of HIV in the city.

5. Death rates were examined in two cities, a Suburban (population: 2,200,000) , and a Metropolitan ( population: 5,300,000 There were 13250 deaths recorded in Metro City from all causes, and 10250 in Suburban City. Heart attacks accounted for some of these deaths. If risk factors associated with heart attack were the same for both cities, which measurement of morbidity would tell us the level of medical support that is extant for heart attack victims in each city? Use anything you can think of to illustrate and defend your answer

6. Several West Chester University students have been complaining of extreme fatigue, restlessness, fever, and sore throat two weeks before finals. You decide to screen them for mononucleosis. Your screening test has the following characteristics:
Sensitivity = 97%,
Specificity = 97%

a) What is the likelyhood that all those who test positive are suffering from mono?

b) What is the likelyhood that all those who test negative do not have mono?