Why you need to know this is well described in Yentis SM. Predicting difficult intubation – worthwhile exercise or pointless ritual? Anaesthesia 2002 ; 57: 105-109.
In the context of difficult intubation :
TRUE/FALSE The sensitivity is the proportion of difficult patients who are correctly identified.
TRUE/FALSE The specificity is the proportion of easy patients who are correctly identified.
TRUE/FALSE As the prevalence of difficult intubation increases the sensitivity will increase.
TRUE/FALSE As the prevalence decreases the positive predictive value increases.
TRUE/FALSE If the test has high specificity it will have a high negative predictive value.