Problem 3 (10 marks in total). You are given the following statistical distribution, which reports the duration in seconds (ti) of the occurrence of some phenomenon. Observation number 1 2 3 4 5 6 7 8 9 10 Total ti 2 20 15 5 4 8 194 443 3 6 700 17 (secs) 4 400 225 25 16 64 37 636 196 249 9 36 234 664 a) (2 marks) Compute the average duration. Specify the unit. b) (3 marks) What is the standard deviation of the duration of the phenomenon? Specify the unit. c) (5 marks) Compute the interquartile range of the duration of the phenomenon. Specify the unit