Problem 10-12 The time needed for checking in at a hotel is to be investigated. Historically, the process has had a standard deviation equal to 146. The means of 39 samples of n = 16 are Sample Mean Sample Mean Sample Mean Sample Mean 1 3,86 3.88 21 3.84 31 3.88 2 3.90 3.86 22 3.82 32 3.76 3 3.83 3.88 23 3.89 33 3.83 4 3.81 14 3.81 24 3.86 34 3.77 5 3.84 15 3.83 25 3.88 35 3.86 6 3.83 3.86 26 3.90 36 3.80 7 3.87 17 3.82 27 3.81 37 3.84 3.88 18 28 3.86 38 3.79 3.84 19 3.84 29 3.98 39 3.85 10 3.80 20 3.87 30 3.96 OU UN Fup 3.86 a-1. Construct an Ichart for this process with three sigma limits. (Do not round Intermediate calculations. Round your answers to 2 decimal places.) UCL LCL a-2. is the process in control