Take the quiz to test your understanding of the key concepts covered in the chapter. Try testing yourself before you read the chapter to see where your strengths and weaknesses are, then test yourself again once you’ve read the chapter to see how well you’ve understood.
A deals with uncertainty and variation
B is census data
C can help establish what works by scientific means
D A and C
2. Outcome measures can be described as
C risk ratios
D A and B
3. Three types of averages are
A 50%, 75%, 25%
B mean, median, mode
C quartile, percentile, quantile
D none of the above
4. To what term does the following description refer?
‘The probability of an event occurring in an exposed group to the probability of the event occurring in a comparison, non-exposed group.’
A relative risk
B odds ratio
C confidence interval
D number needed to treat
5. A well conducted randomised trial comparing a superstatin with a placebo results in an odds ratio of 0.5 what does this mean?
A There is no difference between the groups
B The odds of death in the placebo group are 50% less than the superstatin group
C The odds of death in the superstatin group are 50% less than the placebo group
D More trials need to be done
6. So if the trial comparing Superstatin to placebo stated ‘OR 0.5 95%CI 0.4-0.6’, what would it mean?
A The odds of death in the Superstatin arm are 50% less than in the placebo arm with the true population effect between 20% and 80%.
B The odds of death in the Superstatin arm are 50% less than in the placebo arm with the true population effect between 60% and 40%.
C The odds of death in the Superstatin arm are 50% less than in the placebo arm with the true population effect between 60% and up to 10% worse.
D The odds of death in the Superstatin arm are 95% accurate
7. Which of the following P values suggests that there is a statistically significant difference between two groups:
D A and C