Assessing statistical significance from a confidence interval

Confidence intervals can be calculated for any effect measure, not just relative risk reduction, and can be used to determine if the size of the effect is significant. If the confidence interval includes the value reflecting 'no effect' we cannot rule out the possibility that the intervention has no effect and the result is statistically non-significant. In the table opposite, drag and drop the values of 'no effect' into the appropriate place.

In the table below, drag and drop the values of 'no effect' into the appropriate place.

RR

  • 1

RRR

  • 0%

ARR

  • 0%

NNT

  • ∞
  • 1
  • 0%
  • 0%
  • ∞

Now let us go back to our trial where the relative risk reduction was 33%. It looked good, but was it statistically significant, or might it have occurred by chance? Click on 'yes' or 'no' to indicate your opinion.

Yes

No