HLTH 501 Midterm

HLTH 501 Midterm

HLTH 501 Quiz: Midterm

Module 1: Week 1 – Module 4: Week 4.

1. The median of a group of individuals’ BMIs whose BMIs are 20.47, 21.92, 23.32, 23.41, 25.7, and 30.1 is approximately 24.15.
2. 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.
3. A study is designed to evaluate the impact of a daily multivitamin on students’ academic performance. One hundred sixty students are randomly assigned to receive either the multivitamin or a placebo and are instructed to take the assigned drug daily for 20 days. On day 20, each student takes a standardized exam and the mean exam scores are compared between groups. This study is an example of a Randomized Control trial.
4. The margin of error in a research study is indicative of the precision and accuracy of the research results obtained in the study.
5. An investigator wants to assess whether smoking is a risk factor for pancreatic cancer. Electronic medical records at a local hospital will be used to identify 50 patients with pancreatic cancer. One hundred patients who are similar but free of pancreatic cancer will also be selected. Each participant’s medical record will be analyzed for smoking history. Identify the type of study proposed
6. 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.
7. True/False? Five hundred people are enrolled in a 10-year cohort study. At the start of the study, 50 have diagnosed CVD. Over the course of the study, 40 people who were free of CVD at baseline develop CVD. The prevalence of CVD at 10 years is 10%.
8. The 90th percentile of the standard normal distribution is 1.645.
9. 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?
10. 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?
11. 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?
12. The most widely used measure of variability for a continuous variable is called the standard deviation.
13. Case-control study, prospective cohort study, cross-over trial, and retrospective cohort study are all examples of observational study designs.
14. If there are outliers, then the mean will be greater than the median.
15. 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.
16. 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?
17. The mean is the 50th percentile of any normal distribution.
18. 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.
19. 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?
20. The mean is a better measure of location (central tendency) when there are no outliers.
21. 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 of the 16 individuals test positive for colon cancer, the researchers should determine the sensitivity of the newly proposed screening method is .875.
22. 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?
23. 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.
24. 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?
25. With a binomial distribution with n = 25 and p = 0.48, which is larger?
26. The following table shows the results of a screening test hypothesized to detect persons at risk for side effects of a new cosmetic surgery. Compute the specificity of the test.
27. A clinical trial designed to show the efficacy of a new drug in reducing progression to hypertension reports the following data. Using this information, compute the relative risk of progression to hypertension among patients receiving the new drug as compared to the placebo.
28. A ferritin test is a popular test to measure a person’s current iron stores. In women, ferritin is approximately normally distributed with a mean of 89 ng/mL and a standard deviation of 23 ng/mL. If 50 women are tested, what is the probability that the mean ferritin exceeds 90?
29. A new non-invasive screening test is proposed that is claimed to be able to identify patients with impaired glucose tolerance based on a battery of questions related to health behaviors. The new test is given to 75 patients. Based on each patient’s responses to the questions they are classified as positive or negative for impaired glucose tolerance. Each patient also submits a blood sample and their glucose tolerance status is determined. The results are tabulated below. What is the sensitivity of the screening test?
30. An experimental drug has been shown to be 80% effective in eliminating symptoms of allergies in animal studies. A small human study involving eight participants is conducted. What is the probability that the drug is effective on half of the participants?
31. An investigator wants to test whether exposure to secondhand smoke before 1 year of life is associated with development of childhood asthma (defined as asthma diagnosed before 5 years of age). Give two possible study designs.
32. A pilot study is run to investigate the effect of a lifestyle intervention designed to increase medication adherence in patients with HIV. Medication adherence is measured as the percentage of prescribed pills that are taken over a one-week observation period. Ten patients with HIV agree to participate and their medication adherence before and after the intervention are shown below. Compute the standard deviation of the difference in adherence before versus after the intervention.
33. Approximately 35% of obese patients develop diabetes. Answer the following questions if a physician sees 12 patients who are obese. What is the probability that half of them will develop diabetes?
34. A study is conducted to test a new drug claimed to reduce diastolic blood pressure in adults with a history of coronary heart disease. What is the most efficient study to test whether the drug reduces diastolic blood pressure?
35. A study is run to estimate the incidence of atrial fibrillation (AF) in men and women over the age of 60. Development of atrial fibrillation was monitored over a 10-year follow-up period. The data are summarized below. Using this data, compute the cumulative incidence of AF in men and in women respectively.
36. A study is run to investigate body mass index (BMI) in children living in urban neighborhoods. Based on the following data: compute the sample mean, the sample standard deviation, and the median.
37. Body mass index (BMI) in children is approximately normally distributed with a mean of 24.5 and a standard deviation of 6.2. In a random sample of 10 children, what is the probability that their mean BMI exceeds 25?
38. Four hundred melanoma patients were diagnosed according to the type of skin cancer and the location of the skin cancer. This data is presented below. What proportion of patients had Hutchinson’s melanomic freckle?
39. Glucose levels in patients free of diabetes are assumed to follow a normal distribution with a mean of 113 and a standard deviation of 13. What proportion of patients have glucose levels exceeding 120?
40. Suppose that the probability that a child living in an urban area in the United States is obese is 22%. If a social worker sees 20 children living in urban areas, answer the following: What is the probability that none are obese?
41. The data shown below describe children in four countries in terms of adequate dental care. What is the probability that a child from Mexico has adequate dental care?
42. The faculty and staff at Dana-Farber Cancer Institute in Boston are required to undergo a tuberculosis test each year. Use the following table to answer the questions below. If a Dana-Farber faculty or staff worker goes in to have a TB test, what is the chance of him/her getting a negative test result?
43. The following are body mass index (BMI) scores measured in 12 patients who are free of diabetes and participating in a study of risk factors for obesity. Body mass index is measured as the ratio of weight in kilograms to height in meters squared. Using the following data, compute the mean BMI, the standard deviation of BMI, the median BMI, and the Q1 and Q3.
44. The following are grade point averages measured in a sample of 8 undergraduate students who are applying to graduate schools in public health. Compute the sample mean, the sample standard deviation, and the sample median.
45. The following data were collected in a survey of 8th graders and summarize their cell phone status. What proportion of the 8th graders have cell phones?
46. The following table shows the numbers of patients classified as underweight, normal weight, overweight and obese according to their diabetes status. What is the probability that a patient selected at random is obese?
47. The following table shows the distribution of BMI in children living in United States and European urban neighborhoods. (The data are in millions.) What is the probability that a child living in a U.S. urban neighborhood is obese?
48. The following table shows the results of a screening test hypothesized to identify persons at risk for a rare blood disease. Compute the False Positive Fraction of the test.
49. The gestation period for human births can be taken as normally distributed with a mean of 256 days and a standard deviation of 16 days. If a gestation period is 276 days, what percentile among human births is this?
50. The risk of hepatoma among alcoholics without cirrhosis of the liver is 32%. Suppose we observe 9 alcoholics without cirrhosis. What is the probability that exactly one of these 9 people have a hepatoma?a r