To study bonding between mothers and infants, a researcher places each mother and her infant in a playroom and has the mother leave for 10 minutes. The researcher records crying time in the sample of infants during this time that the mother is not present and finds that crying time is normally distributed with M = 4 and SD = 1.2. Based on the empirical rule, state the range of crying times within which
(a) 68% of infants cried,
(b) 95% of infants cried,
(c) 99.7% of infants cried.