12. The following corrective maintenance task times were observed: (a) What is the range of observations? (b) Using a class interval width of 4, determine the number of class intervals. Plot the data and construct a curve. What type of distribution is indicated by the curve? (c) What is the Mct? (d) What is the geometric mean of the repair times? (e) What is the standard deviation of the sample data? (f) What is the Mmax value (assume 90%)? Task time (min) Frequency Task time (min) Frequency 41 39 37 25 35 31 2 3 2 5 13 10 6 12 12 47 36 23 27 33 17 19 13 4 10 5 7 3 2 8 8 14 11 15 29 21