A television station claims that the amount of advertising per hour of broadcast time has an average of 15 minutes and a standard deviation equal to 1.5 minutes. You watch the station for 1 hour, at a randomly selected time, and carefully observe that the amount of advertising time is equal to 13 minutes Calculate the z-score for this amount of advertising times 0 z = -o,77 O =-1'33 O 2 =0.77 02:1.33