In Exhibit $3-4,$ how many variables are in this data set?

Exhibit $3-4$

The following shows the temperatures $($high$,$ low$)$ and weather conditions in a given sunday for some selected world aties. For the weather conditions, the following notations are used; $c=$ clear; $cl=$cloudy; sh $=$ showers; $pc=$ partly doudy:

$\backslash$table$[[$City$,$Hi$,$Lo$,$condition$],[$Acapulco$,99,77,$pc$],[$Bangkok$,92,78,$pC$],[$Mexicocity$,77,57,$sh$],[$Montreal$,72,56,$pc$],[$Paris$,77,58,c$