Biostatistics Practice Questions and Answers

Question 1: Interpretation of relative risk

Task:

1. The relative risk of developing lung cancer among individuals who smoke is 15.0. Which of the following is the most accurate interpretation of this information?
A) Individuals who have lung cancer are 15.0% more likely to smoke than individuals who do not have lung cancer.
B) Individuals who have lung cancer are 15.0 times more likely to smoke than individuals who do not have lung cancer.
C) Individuals who smoke are 15.0 times more likely to develop lung cancer than individuals who do not smoke.
D) Individuals who smoke are 15.0% more likely to develop lung cancer than individuals who do not smoke.

2. A healthcare provider notices an outbreak of foodborne illness among individuals who attended a holiday cookout. Which study type would be most beneficial in identifying the source of the outbreak?
A) A case series
B) A retrospective cohort study
C) A cross-sectional survey
D) A case-control study

3. A researcher hopes to measure the exposure a large number of individuals who have already developed lung cancer had to secondhand smoke throughout their lifetime. Which study design may prove useful in helping the researcher measure the exposure the individuals had to second hand smoke?
A) A case series
B) A retrospective cohort study
C) A prospective cohort study
D) A case-control study

4. A researcher has a hypothesis that a specific drug may have a higher prevalence of side effects among members of the African American population than members of the Caucasian population. Which statistical technique might the researcher want to use when designing a study to test their hypothesis?
A) Randomization
B) Crossover matching
C) Matching
D) Stratification
5. A new drug is released to market and it has been determined that the drug is responsible for causing hypertension among those individuals who take the drug. If 30,276 individuals were prescribed the drug in its first year on the market and 17,620 individuals developed hypertension, what is the point prevalence of hypertension among those individuals prescribed the drug, after the drug’s first year on the market?
A) 0.00582
B) 0.05820
C) 0.58200

D) 5.82000

6. After attending a church cookout, a number of the attendees are admitted to the emergency room with nausea, vomiting, and diarrhea. After discovering all the individuals admitted to the ER consumed the egg salad at the event, the leftover egg salad was tested and found to be positive for salmonella. If 83 individuals consumed the egg salad and 49 individuals were admitted to the ER with salmonella, what was the cumulative incidence of salmonella assuming that the 49 individuals admitted to the ER were the only ones to be affected by the bacteria?

Question 2: Study type for identifying the source of a foodborne illness outbreak

A) 0.041
B) 0.059
C) 0.410

D) 0.590

7. Drug manufactures of Drug X, which was released on the market 5 years ago to treat Crohn’s disease, have noticed that many individuals treated with the drug have developed drug-induced lupus. A cohort study was conducted for post-marketing surveillance. It has documented that 6 individuals have developed drug-induced lupus over the course of the past 5 years. If 1 individual developed the disease at the 1-year mark, 3 developed the disease at the 2-year mark, 1 developed the disease at the 3-year mark, and the final individual developed the disease at the 4-year mark, what is the incidence rate of drug-induced lupus?

A) 0.0429
B) 0.4290
C) 0.5710
D) 0.9571

8. In which situation would it be most appropriate to use the mean of the set of numbers to describe the data set instead of the median?
A) 152, 157, 159, 163, 164, 165, 976
B) 0, 899, 906, 912, 915, 917, 919
C) 0, 57, 847, 859, 866, 866, 872
D) 165, 165, 177, 178, 186, 199, 211

9. A 95% confidence interval for relative risk of developing a bacterial infection after having a surgery is (3.71, 5.33) when comparing a non-laparoscopic surgery procedure to a laparoscopic surgery procedure. This indicates which of the following?

A) The researchers are confident because the probability that these results would occur is somewhere between 3.71% and 5.33%.
B) The researchers are confident that the probability that these results would occur is somewhere between 0.371% and 0.533%.
C) The researchers are 95% confident that the increased risk of developing an infection is between 3.71 to 5.33 times higher among individuals who had the non-laparoscopic surgery when compared to those individuals who received the laparoscopic surgery.
D) The researchers are 95% confident that the risk of developing an infection is between 3.71 to 5.33 times higher among individuals who had the laparoscopic surgery when compared to those individual who received the non-laparoscopic surgery.


10. Which of the following accurately represents a 95% confidence interval for a sample of 5 individuals whose blood glucose levels were 98, 111, 105, 120, and 147?

A) (153.5, 78.9)
B) (78.9, 153.5)
C) (63.4, 169.0)
D) (169.0, 63.4)

11. With a binomial distribution with n = 25 and p = 0.48, which is larger?

A) P(12 successes)
B) P(9 successes)
C) P(20 successes)
D) P(10 successes)

12. True or False? Biostatistics is integral to the practice of public health because it allows public health professionals to accurately monitor and track the prevalence of disease within a population.

13. True or False? The margin of error in a research study is indicative of the precision and accuracy of the research results obtained in the study.

14. True or False? An active-controlled trial allows researchers to offer participants a placebo in place of an alternative treatment method that has been previously proven to be effective.

15. True or False? Incidence reflects the likelihood of developing a disease among a group of participants free of the disease who are considered at risk of developing the disease over a specified observation period; prevalence involves estimating the proportion of people who have disease at a point in time.

16. True or False? If the odds of catching the flu among individuals who take vitamin C is 0.0342 and the odds of catching the flu among individuals not taking vitamin C is 0.2653, then the individuals not taking vitamin C are 7.7573 times more likely to catch the flu than individuals taking vitamin C.

17. True or False? Histograms are often used to display categorical data, while bar charts are commonly used to display variables that fall on a measurable continuum.

18. True or False? Variability within a sample is oftentimes measured using sample variance.

19. True or False? A newly proposed endoscopy method used to screen for colon cancer is tested among a random sample of the population. Given that 16 individuals from a test population of 100,000 individuals has colon cancer and 14 individuals test positive for colon cancer, the researchers should determine the sensitivity of the newly proposed screening method is .875.

20. True or False? A newly developed medical procedure to prevent death in women who give birth and experience eclampsia has a 97.5% success rate of saving the woman’s life. If a doctor uses this medical procedure in 6 women who experience eclampsia and have no other comorbid conditions, the probability that all 6 women will survive is approximately 0.859.

21. True or False? The mean measure of high density lipoprotein (HDL), or good cholesterol, is 54 with a standard deviation of 17 in patients over age 50. If the HDL values are obtained from a sample of 32 individuals, the probability of getting a mean HDL value over 62 is 0.049.

22. True or False? If there are outliers, then the mean will be greater than the median.

23. True or False? The 90th percentile of the standard normal distribution is 1.645.

24. True or False? The mean is the 50th percentile of any normal distribution.

25. True or False? The mean is a better measure of location when there are no outliers.

26. True or False? Case-control study, prospective cohort study, cross-over trial, and retrospective cohort study are all examples of observational study designs.

27. True or False? For the standard normal distribution, Q3 = 0.675.