Final Exam Bonus Questions 1. Multiple Sclerosis (MS) is hard enough to manage on its own; however, in recent years MS has been linked to depression. Whether it be due to the disease itself or a side effect of drug treatments is still unclear, but the link is undeniable. Suppose in DC 25% were diagnosed with both MS and depression, and 60% had neither. The probability that someone had MS was 0.30. What is the probability a randomly chosen person in DC was diagnosed with Depression? a. 0.35 b. 0.10 c. 0.30 d. 0.75 e. 0.05 2. A researcher wants to estimate the mean systolic blood pressure of a population. A sample of 25 people is taken, and the sample mean systolic blood pressure is 120 mmHg with a standard deviation of 15 mmHg. What is the margin of error for the 95% confidence interval? a. 5 b. 6 c. 7 d. 8 e. 9 3. There is a higher rate of preterm births among African American women compared to white women in the United States. Studies show that higher levels of cortisol among African American women in the United States are associated with preterm birth and other poorer birth outcomes. There was a study conducted comparing the cortisol levels between African American women and white women in the United States. Among 100 African American women (group 1), the mean cortisol level was 7.33 with a standard deviation of 2.12. Among 100 white women (group 2), the mean cortisol level was 3.89 with a standard deviation of 1.43. Assuming the variances are unequal and a 0.5 significance level, use the confidence interval method to test the claim that African American women have different cortisol levels compared to white women in the United States. What is the standard error? a. 0.26 b. 0.19 c. 0.83 d. 0.33 e. 0.07 4. In a research study, investigators compared the mean Blood glucose levels of 24 individuals aged 20-29 who had been intermittent fasting for the past 6 months. The mean BGL was 24.6 with a standard deviation of 4.3. If the mean BGL for the general population is 26.5, using a 0.01 significance level, test the claim that the group of people who intermittent fast have a BGL that is different from those of the general population. What is the null hypothesis H0? a. x(bar) = 26.5 b. x(bar) =/ 26.5 c. = 26.5 d. =/ 26.5 e. None of the above because we need to compare the population mean to 24.6 5. Which of the following scenarios would be appropriate for a matched-pairs t test? a. A trial testing the hypothesis that students in the different school districts within a state have different average scores for a standardized test. This trial includes 12 schools. Population variances are equal. b. A trial testing the hypothesis that students in school A and school B have different average scores for a standardized test. This trial includes two schools, A and B. Population variances are equal. c. A trial of 150 hospital patients testing blood pressure before being given an injection and the patients' blood pressure after receiving an injection. Assume normal distribution. d. Both a and b are correct e. None of the above 6. Exploring the relationship between two categorical variables, the findings about a new drug trial are recorded in the table below. There are 92 volunteers with some disease. The volunteers are split into two groups randomly: control group A and the treatment group B. Volunteers in the control group receive the placebo and volunteers in the treatment group receive the new drug. You conclude that a new drug is effective if people who take the drug recover faster than those in the control group. If your drug is effective, you will invest in its production, otherwise you will look for another drug. Which test must be applied to the table above? a. Pearson chi-square b. One-way ANOVA c. Fisher's exact test d. Independent samples t-test e. None of the above 7. A 78 year old male was admitted to a local hospital with complaints of hip pain, abdominal pain, and fatigue. Initial workup was unrevealing, but the patient was admitted due to concerns for safe ambulation. His stay was relatively uneventful as he underwent laboratory and radiological Success Failure Treatment A 30 10 Treatment B 62 18 tests as well as physical therapy sessions. On hospital day 3, he was noted to be febrile to 100.6F. A rapid COVID-19 test was found to be positive. As it was unclear when his initial onset of symptoms began, contact tracing was performed for his entire hospital stay. Infection control collected the following information: 250 total staff met criteria of being exposed for >15 minutes, with 195 of them stating they wore N95 respirators, and 55 of them wearing surgical mask. Screening testing was undertaken at day 7 after exposure resulting in 12 staff positives among those wearing surgical masks and 10 staff positives among those wearing N95 respirators. What was the relative risk of testing COVID-19 positive for those staff who wore a surgical mask versus those who wore an N95 respirator? a. 3.098 b. 5.16 c. 1.2 d. 4.275 e. 14.23 8. It is estimated that 2 out of 1,000 children in the United States are born with detectable hearing loss. You have begun a study involving these children, and are seeking to recruit at least 30 participants. If your hospital screens 10,000 babies per year, what is the probability that you will be able to identify at least 30 newborns with hearing loss to recruit for your study? a. 1.25% b. 0.94% c. 1.66% d. 2.43% e. 3.16% 9. A researcher wants to determine if MDMA assisted therapy has an effect on post-traumatic stress disorder (PTSD) symptoms in a cohort of US Marine veterans. The researcher gave one dose of MDMA or placebo, along with a therapy session; the veterans were asked to self-report their anxiety levels three days before and after the therapy session. The data is summarized in the table below. ANXIETY LEVELS Decrease No Decrease With MDMA 513 223 Placebo 293 397 Calculate the odds ratio (OR) of veterans who had MDMA assisted therapy and had a decrease of anxiety levels. a. OR= 0.98 b. OR= 1.698 c. OR= 1.067 d. OR= 3.117 e. OR= 1.763 10. A study examining the efficacy of Vitamin D supplementation in the prevention of COVID-19 compared the relative risk of testing positive for COVID-19 in patients with insufficient vitamin D levels versus patients with sufficient vitamin D levels. They found that the patients with insufficient vitamin D levels had an increased relative risk of testing positive for COVID-19, and the 95% confidence interval for the relative risk between the two groups was .63 to 1.20. What can be said about the (2-sided) p value for testing the hypothesis of equal risk? a. The p value is greater than .05 b. The p value is equal to .05 c. The p value is less than .05 d. The p value is 0 e. Cannot be determined from the information given