patients at offices that do not have a wait$-$tracking system and wait times for a sample of patients at offices with such systems.

$\backslash$table$[[\backslash$table$[[$Without Wait$],[$Tracking System$]],\backslash$table$[[$With Wait$],[$Tracking System$]]],[24,31],[67,11],[17,14],[20,18],[31,12],[44,37],[12,9],[23,13],[16,12],[37,15]]$

$0\mathrm{.}48$

$($b$)$ Considering only offices with a wait tracking system, what is the $z-$score for the fifth patient in the sample $($wait time $=12)?($Round your answer to two decimal places.$)$