As its summer time & thoughts of exciting summer camps expanding skills, or time spent catching up with missed opportunities, or indeed just beer & strawberries, are filling our lives it seems appropriate to go entirely left field and explore confidence intervals.
Confidence intervals describe – in terms of interpretation – the range of values where we think the real truth lies (x% of the time – where the ‘x%’ is the number that sits before the CI)*
They are a measure of the precision of our estimate. They can described almost any quantity – the mean, odds ratios, test sensitivity …
Mostly we see 95% CI; this sort of corresponds to our desire for p-values of <0.05. We sometimes see 99% CI – even more sure the truth is in here – or occasionally 90% – wanting desperately to sell us a Thing, usually.
* You’ll note that a 95% CI means we are WRONG 5% OF THE TIME