Reeent research auggeata that Arum-learn rnalte an average of 11] phene calls per day {M August 215, 21110}. Let le number efealla be naturally dieh'ihumd with a standard deviatien ef3 calls. a. What is the pl'bbilil? that an average Ameriean maker. hehueen =1- and 12 call:- per day? b. What is the 'l'hbilil'jl' that an average Hmeriean maker. mere than l5 calla per day? a. "What is the tintnbahilitjfr that an average American makes mere than IE ealla per day\