The Quizzes about Biostatistics

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1.You note that in your practice, a large number of women with a fam- ily history of breast cancer in a first degree relative develop breast cancer You evaluate a number of charts, and find that 5% of the women in your practice who have breast cancer have a family history, but only 2% of women without breast cancer have a family history. Given this information, what is the sensitivity of using family history as a predictor of breast cancer in your patient population?

1. 2%
2. 5%
3. 93%
4. 95%
5. 98%

2. You are reading a population study that reports 90% of people with lung cancer are Thirty percent of the people without lung cancer are also smokers. Given this information, what is the specificity using smoking as a predictor of lung cancer?

1. 10%
2. 30%
3. 40%
4. 70%
5. 90%

3. You are determining whether or not to use a rapid streptococcal anti- gen test to screen for streptococcal You find that that 2% of people with strep throat actually test negative using this test. Of the fol- lowing, which statement best describes this situation?

1. The sensitivity of the test is 2%
2. The specificity of the test is 98%
3. The test has a 2% false negative rate
4. The test has a 2% false positive rate
5. The test has a positive predictive value of 98%

4. You are reading a medical journal and come across an article about The study followed 10,000 patients over 3 years. At the start of the study, 2000 people had diabetes. At the end of the study, 1000 addi- tional people developed diabetes. What was the incidence of diabetes dur- ing the study?

1. 10%
2. 12.5%
3. 20%
4. 30%
5. 50%

5. You are reading a study that compares cholesterol levels in children whose fathers died from a myocardial infarction with cholesterol levels in children whose fathers died from other The p value obtained in the test was <0.001. What does this value indicate?

1. There was no difference in cholesterol levels between the two groups
2. The difference in the cholesterol levels was less than 0.1%
3. There is a less than 0.1% probability that the results obtained in this study were incorrect
4. There is a less than 0.1% probability that the results obtained in this study occurred because of a sampling error
5. If the null hypothesis is true, there is a less than 0.1% probability of obtaining a test statistic equal to or more extreme than the one obtained

6. You are considering using a new influenza screening You find a study that evaluated 1000 patients with this new test. Of these 1000 patients, 400 had the disease. 300 of those had positive tests, and 100 of those had a negative test. Of the 600 that did not have the disease, 200 had positive tests, and 400 had negative tests. What is the positive predictive value of this test?

1. 50%
2. 60%
3. 66%
4. 75%
5. 80%

7. You find that many of your patients that have gone to the emergency department with chest pain have a negative set of initial cardiac Most of those with a negative set of initial enzymes did not have a heart attack. You decide to evaluate 100 of your patients who have gone to the emergency department with chest pain to find out if an initial set of nega- tive enzymes by itself is a good predictor of those that are not having a myocardial infarction (MI). Of those 100 patients, 20 of them had acute MIs. Of those 20, 10 had a positive set of enzymes initially. Of the 80 that did not have an acute MI, none of them had a positive set of initial enzymes. Given this information, what is the negative predictive value of the initial set of cardiac enzymes in your patient population?

1. 20%
2. 22%
3. 50%
4. 89%
5. 100%