The following three questions may help save a persons life:
*Ask the individual to SMILE.

*Ask him or her to RAISE BOTH ARMS.

*Ask the person to SPEAK A SIMPLE SENTENCE (Coherently) (i.e. . . It is sunny out today) 

*NOTE: Another 'sign' of a stroke is this:

Ask the person to 'stick' out their tongue.  If the tongue is 'crooked', if it goes to one side or the other, that is also an indication of a stroke.   If he or she has trouble with ANY ONE of these tasks, call 911 immediately and describe the symptoms to the dispatcher.