Additional Activities (PERFORMANCE TASK, Page 16) Mr. Santos, a teacher at a very small private school, assigns statistics practice problems to be worked via the net. All Grade 7 students must use a password to access the problems and the time of log-in and log- off are automatically recorded for the teacher. At the end of the week, the teacher examines the amount of time each student spent working the assigned problems. The data is provided below in minutes. 15, 28, 25, 48, 22, 43, 49, 34, 22, 33, 27, 25, 22, 20, 39 Find the range, average deviation, variance & standard deviation of the recorded data above.​