A RCT used a sample size calculation for 90% power with a 2-sided alpha of 0.05. A sample size of 438 participants per arm was calculated assuming a 10% relative risk reduction in the primary outcome. Which of the following scenarios would require an INCREASE in sample size? (SELECT ALL THAT APPLY)

A study compares is determining the impact of daily consumption of green tea on systolic blood pressure. Among patients who began drinking green tea daily (n=23) the systolic blood pressure decreased by a mean of 5 mmHg and among patients with no dietary change (n=32) the systolic blood pressure decreased by a mean of 1 mmHg. Which of the following tests would be most appropriate to determine if the results are statistically significantly different?

An L-C circuit has an inductance of 0.596 H and a capacitance of 0.090 nF . During the current oscillations, the maximum current in the inductor is 1.35 A. What is the maximum energy stored in the capacitor at any time during the current oscillations?

A RCT compared occurrence of flares in patients with gout. The results showed febuxostat compared with allopurinol resulted in a HR of 1.07 (95%CI 1.02–1.09). Which of the following statements best describes the interpretation of these results?

The following 4 scenarios are all from double-masked RCTs. Which of the following situations would be at the highest risk for decreased internal validity due to compromised masking?

The magnetic field is uniform over each face of the box in the diagram. With 3.8 T and 9.8 T, the magnetic field at the front surface marked with a ‘?’ is given by:

When is it appropriate to exclude patients with childbearing potential from enrollment in a clinical trial? (SELECT ALL THAT APPLY)

An investigator conducts a study comparing lowopril (a new ACE-inhibitor) to lisinopril in patients with uncontrolled hypertension. The NI margin is set at 6 mmHg. Lowopril lowered blood pressure by 6.1 mmHg and lisinopril lowered by 7.8 mmHg. The difference in blood pressure lowering was 1.7 mmHg (95%CI -0.1 to 3.5). Describe the appropriate interpretation of the results in the context of the NI margin.

An investigator would like to determine the impact of dietary vitamin D on the incidence of bone fracture among children ages 8-10 years. Which of the following study designs would be best for reducing the likelihood of recall bias?

A RCT was conducted to test the efficacy of a new failure heart medication compared to placebo to prevent major adverse cardiac events (MACE). The new medication was found to decrease MACE compared to placebo (RR 0.74; 95%CI 0.46 to 1.02). How is this best interpreted?