One of the following is a measure of central location

In intervention studies investigators do NOT have control over assignment of the exposure to participants  

The control group in a case control study must be free of the outcome under study 

Which of the following study combinations is the correct order in the hierarchy of evidence, from LOWEST to HIGHEST?  A – Systematic review, B – case control, C – Prospective cohort, D– Randomized clinical trials, E-Cross sectional

Which of the following statements best describes a risk ratio (RR) of 5.0 from a study of physical activity and stroke? 

In the hierarchy of evidence, prospective cohort studies are superior to cross sectional studies  

Which of the following sources provide real-time data for detecting outbreaks? 

Through the blinding process, confounding factors become evenly distributed between the study groups  

The researchers were collecting physical and workplace addresses during data collection in a study involving patients on tuberculosis (TB) treatment. Which ethical principle did the researchers NOT uphold?  

4.5 Show by way of calculation that vaccine was protective against measles  WRITE ONLY THE ANSWER, EXPRESSED TO 2 DECIMAL PLACES & NO ROUNDING OFF E.G. WRITE 0.898 AS 0.89